tag:blogger.com,1999:blog-184498202024-03-11T06:40:08.054-07:00~~~~~School Bus MechanicMechanical Repairs & Troubleshooting On Diesel Engines, School Buses and Related Operating Systems.Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.comBlogger327125tag:blogger.com,1999:blog-18449820.post-87347016054891293752018-07-13T14:31:00.001-07:002018-07-16T22:41:06.330-07:00School Bus Mechanic Moving to MechanicsHub on YouTube<div class="separator" style="clear: both; text-align: center;">
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Hello and thank you for visiting my schoolbusmechanic blog. I have been posting here since 2006 and have 326 blog posts. I'm very grateful to those of you who have followed me through the years. The mission when I got started was to share with the internet community what the job and responsibilities were for the average school bus mechanic.<br />
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Some people would ask me if I was off for the Summer or didn't think there was much to do around the shop. On the contrary there is a shopping list of work on a school bus fleet including motor vehicle inspections, services, repairs and maintenance in other words "non stop work".<br />
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I want to let you know that this blog will remain as is and will not be taken down due to the volume of information starting from 2006. Some of the videos are not showing up because I have moved them to a YouTube channel that I have partnered with called <b>Mechanics Hub.</b><br />
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They find mechanic jobs for companies all over the world and asked me to post videos to their channel and articles on their <a href="https://www.mechanicshub.com/toolbox/articles/" target="_blank">website</a>. Below is the link to their Youtube channel where all of my videos are located. Most of the videos have links in the description to the article on the Mechanics Hub website.<br />
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So please click the link below and<b> 'subscribe'</b> to receive all of my uploaded videos.<br />
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<a href="https://www.youtube.com/user/MechanicsHubdotCom">https://www.youtube.com/user/MechanicsHubdotCom</a><br />
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I hope to see you there and as always send me your questions in the comments.<br />
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Regards,<br />
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JohnAnonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-24728405517561036862018-02-12T21:51:00.000-08:002018-07-16T22:42:39.777-07:00MaxxForce DT Diesel Engine Injector Miss in a School Bus <br />
An injector miss isn't too hard to detect since the engine code that showed up on the dash indicated a missing injector. This involved replacing the injector and a couple of seals on pressure sensors. The oil manifold is heavy and takes some work to move it on and off the top end of the engine. Once the injector is replaced and the hold down is torqued (22 ft lbs) the manifold sits on top supplying the high pressure oil from the HPOP (high pressure oil pump).<br />
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This high pressure system can get up to 4500 psi so if there are any weak spots and a leak develops the injectors stop firing properly.
One test that really works well is to remove the main oil feed hose from the high pressure manifold and apply shop air to the manifold seeing if there are any leaks. If so there may be a failed seal someh where in the system.<br />
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If there are no leaks then there's a possibility of a bad IPR (injection pressure regulator) that screws into the HPOP controlling the pump output or the pump it self is not putting out pressure. Is this common? unfortunately yes we have changed out a HPOP and they are not cheap! $1700.00 while an injector runs around $500.00 which is Canadian funds. Yes it can a big owwie on the pocket book with these diesels.
So I wanted to suggest something to anyone who runs MaxxForce engines.<br />
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They are bad for premature engine wear so the easiest solution is to shorten engine oil changes. We are now changing engine oil at 6000 mile (10,000 km). It's a cheap alternative compared to a premature inframe. Our fleet has had to rebuild 4 of our 2010 - 2011 DT engines due to no compression / high blow by situations. This really drives up the costs replacing pistons, liners, rings bearings, cylinder rebuild etc.<br />
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The labor on top of all this adds to the cost and down time. Another thing that would be worth going for is engine oil samples so engine conditions can be analyzed well before obvious problems occur. The results from engine oil testing covers everything from metals, fuel or coolant contamination. Well worth the cost! That's all I have to say about this subject. Leave a comments or questions below. Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-49795713858621164242017-12-25T13:46:00.000-08:002017-12-25T13:46:33.730-08:00Mercedes MBE Diesel Engine Pusher School Bus<iframe allow="encrypted-media" allowfullscreen="" frameborder="0" gesture="media" height="315" src="https://www.youtube.com/embed/YE8BX7T76-w" width="560"></iframe>
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The cold start on this bus was perfect without any hold ups. It was plugged in and the batteries are obviously in good shape. Of course with most diesel engines the white smoke is normal with incomplete combustion going on. Heat from compression is low in this case so it takes a while for normal combustion temperatures to occur. The rule of thumb with diesel engines in my book is to put the engine to work as soon as you get normal oil pressure or at least make sure the high idle mode is on. Idling a diesel in cold weather is not a good practice because of the build up of carbon and related combustion byproducts that happen with cold starts.<br />
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These MBE 900 diesels are good solid engines except for the emissions which was adapted to the original block in 2007. The blocks can not be swapped from non emissions to these 2007 models because of added modules that were engineered to meet emission standards. I know this from experience we have a 2008 MBE that has a cracked block and no one can find me a bare block for it. There are plenty of non emission blocks around but nothing newer. The long block is available from the dealer but at a huge cost and a core charge that we would not get back due to the crack in the block.<br />
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When the warranty was up with these engines we were in for a lot of challenges. The engine codes were running away on us with daily occurrences with the EGR valves, DPF diesel particulate filter, EOS electrostatic oil separator along with boost and charge air codes that did not let up. Two of these pushers were sports run buses and almost every trip they would radio back and tell me the engine was coding. One saving grace was the ignition key could be cycled on and off which would reset the code until it came back again. But this would stress me out regardless being helpless with the bus so far away. One bus was 4 hours out of town and I spent hours trying to line up a service call to do a parked regen or else the bus was dead in the water.<br />
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Eventually these 2 bad boys were taken off of the sports run and we started using newer Cummins ISC diesel engines. The pressure was off and if you have read any of my other posts Cummins is my choice for a diesel engine medium duty ISB and ISC models. Yes they don't last forever there are quirks and failures but an extremely smaller percentage compared to other diesels on the road. Preventive maintenance had proven to extend down time and the extra cost is money well spent.<br />
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Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-17267877459106131452017-12-04T22:24:00.002-08:002017-12-04T22:36:21.001-08:00Cummins ISB Diesel Engine Ranks At The Top <iframe allowfullscreen="" frameborder="0" height="360" mozallowfullscreen="" src="https://player.vimeo.com/video/155084717" webkitallowfullscreen="" width="640"></iframe>
<a href="https://vimeo.com/155084717">Cummins ISB Diesel Engine Running</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
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Just listen to that baby purr...doesn't it sound great? Cummins has won the "who makes the best medium diesel engine contest". These engines excel way beyond all others on the market. Caterpillar and Navistar collaborated with the MaxxForce design using HEUI injection and it could not keep up with emissions and those of us who still operate them are paying through the nose with repairs and labor to keep them on the road. Production has ceased for all MaxxForce diesel engines in the medium duty industry along with the latest shut down of the 9 and 10 models.<br />
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Mercedes MBE 900 engine manufacturing shut down years ago because of the same reason not being able to pass the emission standards. We still have several of these engines running in our fleet and are kept on our toes dealing with emission issues. They have a sturdy block and top end but could never keep the engine clean enough to run the way it should have in the first place. Soot and ash is everywhere causing constant driveability problems.<br />
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More reasons why my top pick is the Cummins ISB. It has the SCR system developed by Cummins engineers to reduce emissions down to Hydrogen and water. In other words zero levels of harmful oxides of nitrogen that pump directly out of diesel engine combustion chambers. Cummins uses diesel exhaust fluid to inject into a catalyst combined with the original diesel particulate filter design forcing bad emissions to it's knees. Our fleet will be nothing but Cummins ISB from here on in. There will be no guinea pig testing with us anymore with new diesel engine designs that salesman push with their over-enthusiastic promotions.<br />
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Sorry guys that's not going to work in our fleet. We've got our hands full trying to keep up with inferior diesel engines that fail constantly and pick away at our operating budget. It's easy to talk the talk but we are the ones that end up pulling our hair out for years. I would like to thank Cummins for designing the ISB diesel engine with the end user in mind. Everything that has to be serviced is easy to reach... your software is excellent and down time is minimal. Think red...Cummins red if you're thinking about buying a truck or a bus. You will keep a lot more cash in your wallet and you'll spend a lot more time on the road.<br />
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<br />Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-22899287914362321922017-09-11T23:03:00.002-07:002017-09-12T19:53:34.514-07:00Mercedes EGR Valve Test<iframe allowfullscreen="" frameborder="0" height="360" mozallowfullscreen="" src="https://player.vimeo.com/video/158289540" webkitallowfullscreen="" width="540"></iframe>
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The EGR valve on this Mercedes MBE 900 diesel engine was under suspicion so we hooked up the software and went into the test mode. The valve can be moved to any desired position using the software which indicates if the EGR is faulty or not. In the video the valve moves correctly when manipulated by us.<br />
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It's controlled by an electric motor that I have seen fail on occasion. Usually an EGR valve code will come up once the valve moves in the wrong direction. If you are unfamiliar what this valve does I will explain it's purpose. EGR cooled exhaust was one of the first designs in the engineering department by factory engineers to combat the levels of Nitrogen Oxide or NOx.<br />
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By cooling the exhaust before it enters the intake system the NOx is reduced with lower exhaust temperatures and less oxygen levels. The disadvantage of this process is soot levels are increased with cooler exhaust levels in the combustion chamber. The DPF filter takes care of this down the line as long as the engine is worked hard and there are no mechanical issues like extra fuel or oil getting into the combustion chamber.<br />
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The onboard computer controls the open and close routine of the EGR Valve. Up to 50% of the exhaust is routed into the engine intake according to the performance setting in the software. Different loads and speeds dictate the EGR settings. When the computer commands the valve to open to a certain percentage and it does not an engine code pops up. Poor engine performance will be the first sign there is a problem.<br />
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Without the engine software your hopes are slim to none figuring out the problem. Codes are explained very well and most times it will lead you down the right path. That's it, emissions are here to stay and EGR valves are essential to control NOx.Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com2tag:blogger.com,1999:blog-18449820.post-6560078974262962052017-03-05T14:09:00.002-08:002017-09-12T19:53:53.216-07:00School Bus Automatic Transmission Control Module<iframe allowfullscreen="" frameborder="0" height="360" mozallowfullscreen="" src="https://player.vimeo.com/video/172368946" webkitallowfullscreen="" width="540"></iframe>
<a href="https://vimeo.com/172368946">School Bus Allison Automatic Transmission Control Unit</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
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School buses these days come with Allison automatic transmissions. In my opinion there's no other choice for running gear. Allison has got it nailed with engineering design and software. We just purchased the newest Allison software and it does a nice job of laying everything out with troubleshooting and tutorial videos all in one. Recently one of our Navistar conventional buses was on a field trip and called in with the transmission not wanting to shift.<br />
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I went out and for some reason after cycling the key a couple of times the bus was limped back to the shop. The basic checks are transmission codes and wiring connections, bad wiring from the TCU to the transmission. The code P0614 was a torque data fault which is a communication problem between the TCU and ECU (engine module). There is no schematic to follow it's all about how much torque the transmission will allow from the engine.<br />
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This feature was put into place to protect the transmission from damage if for some reason i.e. the engine delivers too much torque due to over fueling. After checking all of the pin connections and the wiring the J1939 resistance was checked and we got a reading of 57 ohms which is normal. If you're not familiar with J1939 it is the network of communication between all of the vehicle control modules.The engine, transmission, ABS brakes, body control module etc.... so if there is an issue with this system the messages will not connect properly and strange things start to happen.<br />
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The green and yellow twisted pair of wires goes to each module so a high speed signal will occur when the operator wants to shift into a certain gear or signals the ABS module that braking is taking place and so on. The modules read it's sensors and adjusts to accommodate any changes such as driving up a hill or coasting on the highway. When there is a bad wire in this twisted pair the messages will be all mixed up and something in the operating system will fail followed by a fault code on the dash alerting the driver.<br />
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A great advantage we have running a fleet is there are buses with the exact same specs. which gives us the ability to swap modules to cancel it out during troubleshooting steps. In the case of the P0614 code when we changed the TCU with a good working unit from another bus the code disappeared. This saves the guessing game and the rules are when you order an electronic part and use it you own it. The price for these modules are well over a thousand dollars so be sure before you order one. They have to be specially programmed according to the part number of the original module and the specs related to the vehicle serial number so I'm sure returning it would be a hardship.<br />
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Thanks for reading this post I hope it helped out!! <br />
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<br />Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com3tag:blogger.com,1999:blog-18449820.post-69057914120572232422016-11-03T22:04:00.000-07:002016-11-03T22:33:03.391-07:00Mercedes MBE 900 Diesel Particulate Filter Cleaning <iframe allowfullscreen="" frameborder="0" height="360" mozallowfullscreen="" src="https://player.vimeo.com/video/169049736" webkitallowfullscreen="" width="540"></iframe> <br />
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The emission controlled diesel engine causes a lot of soot and ash build up through out the intake and exhaust system. The sticky GOO that invades literally every square inch of the engine's components has to be removed by way of passive or parked regenerations or physically cleaning off the build up before it's too late.<br />
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The video shows us using a household cleaner to soak the diesel particulate filter from a Mercedes MBE 900 diesel engine. This filter was condemned by one of the local shops we took it to for cleaning. They baked it at extreme temperatures to remove as much residue as possible. In this case the test for flow was too low for them to give it a pass.<br />
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So our options were to buy a cleaned DPF from the Mercedes dealer for $800.00 or experiment on our own with 'Mr Clean'.
In the past we've used it to flush out cooling systems when there's oil contamination or for removing soot from small emission parts but this was something we wanted to try since there was nothing to lose. Mr Clean is an excellent degreaser so our plan was to let the DPF soak for 2 days and thoroughly steam clean it off.<br />
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I'm happy to report that since reinstalling this DPF there has been no fault codes for close to three months.
The typical 2631 code (turbo boost performance) has not reared it's ugly head for some time now. Since then we've done 2 more buses with the same success. How long until the DPF starts to get plugged up again is hard to say.<br />
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They're supposed to be serviced or replaced around 150,000 km according to the Mercedes estimate but that's up for discussion. The plastic drum we used to soak the filter was a used DEF container. One gallon of Mr. Clean is all it takes to get a good strong solution.
The soot and ash collected on the filter is liquified so when you use the steam cleaner it comes out looking really good.<br />
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Another thing we do is clean contaminated sensors and reuse them instead of spending 50-60 dollars each. Replacement parts for emission controlled diesel engines are expensive so any shortcuts or experiments that work is a bonus :)Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com2tag:blogger.com,1999:blog-18449820.post-69892391294342052032016-05-06T11:04:00.001-07:002016-11-03T22:33:34.481-07:00Park Brake Not Releasing C2 School Bus<iframe allowfullscreen="" frameborder="0" height="360" mozallowfullscreen="" src="https://player.vimeo.com/video/150753913" webkitallowfullscreen="" width="540"></iframe>
<a href="https://vimeo.com/150753913">Park Brake Not Releasing C2 School Bus</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
The park brake on a Thomas C2 school bus has an interlock that requires the service brake to be applied before the park brake releases. Most of the issues we had was the stop lamp module and park brake module located at the air management unit depending on the year of the bus the bank of modules are at the very back in front of the differential housing or behind the transmission.<br />
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There was a recall years ago regarding the stop lamp switch located on the right side of the AMU looking towards the back end. The problem was the internal switch wasn't contacting properly so Thomas revised the design and there have been very few problems since then. If you go into accessfreightliner you can bring up the AMU layout for the VIN you're working on.<br />
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The park brake light on the dash is a warning to the driver not to drive away with the park brake on, When a driver pulls out the park brake valve the modules sense this and through the J1939 messaging system air pressure changes trigger a signal that is sent back to the dash illuminating the park brake light. When you come to a stop and shut down the engine if the park brake valve is not activated this triggers an alarm until the park brakes are applied.<br />
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Unless there's an air leak most of the trouble with AMU modules is the switch contacts. The first check is to see if the brake lights are working if not the stop lamp switch in the module can be tested by jumping the signal to the bulk head module bypassing the internal switch in the module. If the brake lights work there is a problem internally with the stop lamp module.<br />
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The same test can be done with the park brake module. In the video the two terminals that sends signals to the BHM are jumped and if the park brake indicator light comes on then there is an internal problem in the module itself. There are only two wires to this module so it's a straight forward test. Most of our troubles have been with these 2 modules.<br />
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Also you can not rule out opens and resistance in the wiring harnesses. This is another possibility that you might have to deal with. If you have a Freightliner dealer in your city you need to get a user and password to the accessfreightliner website. Here you will find the schematics and troubleshooting required to fix an electrical problem. Without this information it's very difficult to blindly find an electrical fault especially with multiplexing that's here to stay for a long time.Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com10tag:blogger.com,1999:blog-18449820.post-86875184630493409402016-03-02T22:57:00.000-08:002016-03-02T22:57:31.360-08:00Hard Start DT466E<iframe allowfullscreen="" frameborder="0" height="375" mozallowfullscreen="" src="https://player.vimeo.com/video/92141947" webkitallowfullscreen="" width="500"></iframe>
<a href="https://vimeo.com/92141947">DT 466 ENGINE OIL PUMP</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
The regular engine oil pump supplies the HEUI high pressure pump so since the supply wasn't meeting the demand we had a hard start situation. The engine oil pressure regulator appeared to be scored so we attributed the lower oil pressure to that defect.<br />
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The oil pump drive and gears had looked alright but who knows what a little wear will do. It could be thousands of an inch causing problems. So after replacing the pump and regulator and using 0W40 oil for the cold start season starting improved drastically.
Once we pulled the engine hood off of this bus which was a conventional international 4300 getting at the parts was a breeze.<br />
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There was no laying on our backs except for removing the oil pan. One characteristic with all of our DT466E diesel engines was they ran like crap when they were cold. It took some time for the oil pressure in the high pressure side to regulate itself and provide the oil pressure to the injectors. A lot of injector problems were with the injector o-rings that separate the oil from the fuel. They would deteriorate and create an engine miss.<br />
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The last of these buses got sold to a church group who took them down to Guatemala. They shipped them by boat the second time around because of an incident while travelling through Mexico. Those road blocks cost a lot of money and you have to watch your back at all times. I talked to a Mechanic who just left to go down there and so some repairs. I hope he has all of the tools and parts he needs. The technology down there is not up to speed so if something breaks it gets fixed in what ever way possible.<br />
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The DT466E being electronic needs diagnostic software to analyze faults so I hope the 2 engines stationed down there last for a long time and don't give them grief. I donated a few old parts sitting on the shelf for the air dryer. The mechanic said the air compressor isn't building up very fast. The air dryer most likely needs servicing since it takes out all of the \moisture and oil from the system. Leave it too long and a restriction will build up slowly but surely. <br />
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<br />Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com2tag:blogger.com,1999:blog-18449820.post-7520649738293705132016-01-20T23:21:00.001-08:002016-01-20T23:25:04.403-08:00Mercedes MBE 900 Parked Regen
<iframe src="https://player.vimeo.com/video/144081416" width="500" height="281" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>
<p><a href="https://vimeo.com/144081416">Using Mercedes Software To Perform a Regen</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com">Vimeo</a>.</p>
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In 2007 everything changed for diesel engines. The newly integrated emission systems were now the most important cog in the wheel. They had to meet certain parameters according to the onboard computer programming and if they did not an engine code would appear and stare you in the face until the fault was repaired. At first it was frustrating since we had not worked extensively on these emission controlled MBE 900 models.<br />
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The Mercedes dealer become regular aquaintances and saw our buses many times over the 5 year warranty period. Engine codes appeared then went away and popped back up again a couple of days later and so on. Once warranty expired we knew it was time to get into these engines more than ever. The online resources called DDSCN was very helpful along with the Detroit Diesel engine software we had loaded up on our laptop.<br />
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There was a lot to absorb since everything was monitored by the MCM (motor control module). Turbo boost, EGR and diesel particulate filter cleanliness determined how well these engines were going to run. Once there was a restriction in the DPF a regular code 'dpf out of range high' would pop up until we did a parked regen or repaired a sensor or plugged up sensor air line. Without the diagnostic software we could not do a thing to get these engines back in shape.<br />
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The DPF section in the software allows you to watch all of the temperatures in the DPF and DOC. The differential pressure indicated if there was a restriction (3 psi max). The video goes into a parked regen where the temperatures go as high as 1,000 degrees cooking out the DPF. This half hour process does the job and most times it makes a huge difference in driveability.<br />
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Another option to troubleshooting was an over the road regeneration where you could monitor the regen process while on a road test and record the data. The Detroit Diesel software is very good for narrowing down a problem. Once there is a code the software can troubleshoot the code step by step which really made life easier for the techs.<br />
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The filter cartridge in the DPF is replaceable which we had to do a few times because the regen process was not working. It's similar to an air filter that you clean out and stick back in the cannister. Eventually it's not going to clean up properly over time due to the compounded accumulation of debris. Soot and ash are a never ending problem throughout an emission controlled diesel engine and the MBE had lots of that with sensors plugging up and EGR valves sticking.<br />
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They are definitely not the perfect engine when combined with emissions but working on them and gaining experience helped our shop know what steps to take whenever a fault occurred. <br />
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<br />Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-75692940234803589532015-11-28T22:13:00.000-08:002015-12-06T11:57:41.102-08:00Air Brake Job Using Machining Tools<iframe allowfullscreen="" frameborder="0" height="375" mozallowfullscreen="" src="https://player.vimeo.com/video/94485621" webkitallowfullscreen="" width="500"></iframe> <br />
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<a href="https://vimeo.com/94485621">Machining School Bus Brake Shoes</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
The lathe in the video makes a complete cut on the brake shoe allowing 100% contact. This is necessary when a chatter or brake pulsation is occurring with brakes applied. We used to machine all of our brake shoes on all brake jobs but found it to be time consuming. Now we replace the drum and shoes plus hardware.<br />
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There have been some cases where the contact is not favorable and machining was necessary.
Our buses use all sizes of brake shoes from 6 inch on the steering axle to 8.5 inches on the drive axle. All air brakes come standard with automatic slack adjusters. I talked to a sales rep from Canadian Brake and he says there are still customers who purchase manual slack adjusters. I haven't seen one of those for years.<br />
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Since we run a fleet of school buses it's policy to replace the auto slacks every brake job. There is only one drive axle so 200.00 for a couple of slacks is nothing. Spring brake pots get replace every 5 years. Our choice is to use MGM piggy back pots because of their superior quality. For an extra 50.00 that's great insurance.<br />
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A few months ago I attended a trade show in town and talked to the Haldex slack rep and he informed me to not grease them too often. This will disable the mechanism with the hydraulic effects of the grease. We have auto grease systems installed on our S cam tubes and slack adjusters. That has caused grease leakage on to the brake shoes from over greasing which is picked up by the government vehicle inspectors.<br />
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If it's bad enough the wheel has to be removed and shoes cleaned up. This is a procedure we want to avoid so now we advise the auto grease system installers to avoid hooking up to those areas including the steering box bearing. That's another spot the DOT makes notes on during their fleet inspection thinking it's a seal leak.<br />
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Getting back to the brake lathe it does wonders on pesky brake problems that the operator experiences. There was one time when we just kept machining down the shoe material until there was a total 100% contact to fix a pulsation. The drums had to be machined as well. There was a lot of material removed to accomplish this but the front brakes last twice as long as the drive axle brake so it was worth the labor to do so.Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com2tag:blogger.com,1999:blog-18449820.post-75741016157928500542015-10-04T10:48:00.000-07:002015-10-04T10:48:21.458-07:00Cat 3116 Tune Up Tools and Procedures<iframe allowfullscreen="" frameborder="0" height="375" mozallowfullscreen="" src="https://player.vimeo.com/video/97302246" webkitallowfullscreen="" width="500"></iframe> <br />
<a href="https://vimeo.com/97302246">CAT 3116 Diesel Engine Tune Up</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
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<b>Cat 3116 Injector Adjustment</b></div>
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The video shows how the Cat Tuneup Tool
Kit works on a 3116 diesel engine. When the injector is installed I
find it's easier to place the dial contact on the injector by feel
and then having a look to make sure it's seated properly. In the Cat
tune up kit you need the dial indicator, contact point, timing gauge
block and magnetic base.</div>
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On top of the valve cover is a data
plate that has the factory timing spec. This is the reading that you
need to stick to when the timing tool is all set up. First of all you
need to preset the dial indicator on the timing gauge block and set
it exactly to 62.00 mm.
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Rotate the engine so cylinder #1 is on
the compression stroke. Both valves will be closed and cylinder #6
will be on the exhaust stroke. Injectors 3 5 6 can be set in this
position along with 1 2 4 intake and 1 3 5 exhaust valves. (Intake
.015 in exhaust .025 in) The injector spec on the valve cover can
vary plus or minus .020 mm.
</div>
<div style="margin-bottom: 0cm;">
<br /></div>
<div style="margin-bottom: 0cm;">
Rotate the engine 360 degrees and
adjust the remaining valves and injectors. The Cat tool kit comes
with a manual and gives you a detailed step by step procedure for
these adjustments. It's a fussy operation but once everything is set
these engines run very nicely. Keep the valve adjustment on a regular
schedule because of a weakness in the exhaust valve stems that blow
apart if there running at high temperature and rpms.
</div>
<div style="margin-bottom: 0cm;">
<br /></div>
<div style="margin-bottom: 0cm;">
I hope the video gives you a better
idea what's involved with injector set up on the 3116. The entire
tune up kit is pricey and the last time I checked it was up around
$4000.00 Canadian. We had to purchase it however that was in the mid
1990s and we paid much less than that. You can not get away with
setting up these engines (except valve adjustment) without the kit.
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Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com9tag:blogger.com,1999:blog-18449820.post-51439215374669494072015-09-24T21:17:00.001-07:002015-09-24T21:17:19.220-07:00Cummins ISC Diesel Engine Turbocharger Failure<iframe allowfullscreen="" frameborder="0" height="281" mozallowfullscreen="" src="https://player.vimeo.com/video/112136884" webkitallowfullscreen="" width="500"></iframe> <br />
<br />
<a href="https://vimeo.com/112136884">Cummins ISC Turbocharger Replacement</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
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This failure occurred without any notice. In the video you can see the nut that loosened off and backed right off of the turbo shaft. Once this happened it caused seizure and a large amount of oil started pumping through the intake system. The turbo bearings are lubricated with pressure engine oil so there's a big mess when this type of failure happens.<br />
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The oil did help in a way flowing into the charge air cooler and leaking out a crack in the cooler core. So replacing the charge air cooler was added to the list. Once the turbocharger was replaced with a re-manufactured unit along with the charge air cooler this engine was back in business. It's important to flush out the air piping in case debris got trapped. The steam cleaner does wonders for this type of task.<br />
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Preventing this failure would be hard to do since normal preventive maintenance does not involve removing air intake and boost piping for inspection during a service. This would take too much time so the only other clue would be poor boost performance or turbocharger noise audible to the mechanic or driver.<br />
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I hope you find this video informative as food for thought. A failure of this kind will happen again undoubtedly somewhere...somehow. It falls under the "how the hell did that happen" category. If you have a comment please state it below. I like to get feedback form readers who have gone through something similar.<br />
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Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com1tag:blogger.com,1999:blog-18449820.post-81551270140000740622015-09-21T10:18:00.002-07:002015-09-21T10:18:40.751-07:00School Bus Pusher Radiator Removal Shortcut Changing the radiator or removing it for repair at the local radiator repair shop is a big operation on the pusher school bus. The charge air cooler, oil cooler and radiator are sandwiched on top of each other making it hard to get the radiator out of the chassis. <br />
<br />
The objective in this video is to show you a short cut that all mechanics love to do saving time and some frustration.
The way we do it is to support the upper components and loosen off the radiator mounts. The frame supports have to be loosened as well to allow space so the the rad core can be removed freely. <br />
<br />
The cooling fan which is a Parker system is braced to the main frame around the radiator so it needs to be chained up out of the way.
In most cases if the radiator is original and has a leak the chances of repairing it is remote I'm sorry to report. <br />
<br />
This rad core is over 12 years old and has gone through a lot of weather and road debris kicking up into and around the core area on a daily basis. There are cores out there but we had to get one from Thomas buses.
I hope this video helps you bus mechanics out there. <br />
<br />
I would appreciate it if you shared or commented on this post. It's great to get some feedback from others who have had similar problems and found a faster way to get them done. Time is a precious commodity in a fleet garage and with that said I'll continue to share videos on repairs that will help out fellow mechanics.
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<br />
<strong>Watch the video below on what our shop did to remove the radiator on a pusher school bus:</strong>
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<iframe allowfullscreen="" frameborder="0" height="281" mozallowfullscreen="" src="https://player.vimeo.com/video/131318663" webkitallowfullscreen="" width="500"></iframe> <br />
<a href="https://vimeo.com/131318663">Radiator Repair Thomas Pusher School Bus</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-67110819862544422852015-08-13T10:12:00.000-07:002015-08-13T10:29:24.419-07:00A Common School Bus No Start Problem <span style="font-size: large;">Thomas School Bus Vandalock
</span><iframe allowfullscreen="" frameborder="0" height="281" mozallowfullscreen="" src="https://player.vimeo.com/video/99885801" webkitallowfullscreen="" width="500"></iframe> <br />
<br />
This a common no start problem with all school buses and will continue to be since Vandalocks are standard equipment. The Vandalock as the name states locks out the start circuit and locks the access entries to the inside of the bus. The Thomas pusher in the video does not have any lock out for the entrance doors just the side door and rear emergency exit window.<br />
<br />
However there's a cheap and easy solution which is to purchase a metal bike lock (u shaped) and install a couple pieces of angle iron to the entrance door leafs. We only do this with our sports run buses which do a lot of out of town trips. Just recently one of our sports run pusher buses were in Vancouver and the batteries got ripped off.<br />
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This is the first time this has ever happened to us perhaps because of the high return for lead at the scrap yard or someone with a truck needed a good set of batteries? Who knows but it's the sign of the times so a lock will be going on both of our sports run battery doors. The service call cost $800.00 in total so a couple of $20.00 hinge locks is a solid investment.<br />
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Getting back to the Vandalock system...when we talk to our drivers over the radio we can usually run them through the steps to check all of the exits to see if the latches are either locked or unlocked. One of the students could have very well kicked the latch closed since it's in the perfect spot on the side exit door as seen on the video.<br />
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The buzzer will stay on with the ignition key on with no engine crank until the latches are disabled. Vandalock systems are great to have as long as everybody is trained properly.<br />
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<span style="font-size: large;">International School Bus Vandalock </span><br />
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<iframe allowfullscreen="" frameborder="0" height="375" mozallowfullscreen="" src="https://player.vimeo.com/video/93819972" webkitallowfullscreen="" width="500"></iframe> <br />
<br />
The International school bus vandalock is the same principle as Thomas buses but designed totally different. The conventional models have the entrance door and the rear door set up to lock out access and the engine start system. The video demonstrates how it works but the there is a minor flaw with the lever that activates the micro switch above the entrance door.<br />
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This micro switch has to be activated for the bus to start. Every year we have no start problems because of the lever dropping down while the bus is enroute. A rough road condition will cause this and the lever will drop down deactivating the switch causing an engine no start ... alarms will stay on while the ignition is turned on. One solution is to tighten the lever fastener to increase resistance but ever so slightly so the activating rod has enough push to move the lever.Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com3tag:blogger.com,1999:blog-18449820.post-27728881826493283882015-07-23T23:10:00.001-07:002015-07-23T23:12:35.195-07:00Cat 3116 Tune Up Steps<iframe allowfullscreen="" frameborder="0" height="375" mozallowfullscreen="" src="https://player.vimeo.com/video/92487749" webkitallowfullscreen="" width="500"></iframe> <br />
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The 3116 Cat diesel engine tune up is quite involved because of the rack that controls the fuel injection system. The synchronization of the rack is the first step once the injectors are installed. The rack is mounted and torqued down on top of the head linked up to each injector rack.<br />
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The injectors must have hold downs installed on top of the return springs so the injector rack moves freely.
The hold downs are included in the tune up kit. The #1 injector rack is non adjustable because it's calibrated at the factory. The tune up tools include a calibration fixture that has to be set up on #1 injector to enable the remaining 5 injectors to be synchronized.<br />
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After synchronization the full fuel setting is checked followed by injector timing and finally the valve setting.
This is an extremely abbreviated explanation on setting up a Cat 3116 and without tools and some training it makes this job a tough one. The engine valve clearances can be checked but the rest definitely needs the tune up kit to complete the job properly.<br />
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Once going through the steps a couple of times setting these engines up it gets easier. Following the manual works it just takes time to get the calibration settings correct.
Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-15958054148721142742015-07-14T23:45:00.000-07:002015-07-14T23:47:06.245-07:00School Bus Photos 1997 Thomas Pusher <iframe allowfullscreen="" frameborder="0" height="375" mozallowfullscreen="" src="https://player.vimeo.com/video/93765068" webkitallowfullscreen="" width="500"></iframe> <br />
<a href="https://vimeo.com/93765068">Thomas School Bus Photos</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
Oh the memories....this 1997 Thomas school bus pusher is long gone but the photos tell it all. Back then our fleet had 13 Cat 3116 diesel engines. From new they were nice and shiny without any problems until suddenly several of them experienced an intermittent transmission shift episode.<br />
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We searched high and low for the fault and scratched our heads and even got the dealer involved thinking ...warranty??
Well what it ended up being was a corroded battery supply wire from the battery to the shift module and transmission control unit.<br />
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There was a butt splice half way down the frame which wasn't sealed with heat shrink or soldered at all. The crimped connector was blue with corrosion and caused the battery feed to cut in and out or it would totally cut out and our bus was dead in the water.<br />
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The transmission shop would not give us warranty because the harness was OEM from the factory. So there was some discussion on who pays but it all came out fair at the end. The wiring was all hard wired (no multiplexing) and searching for problems in wiring took a lot of time.<br />
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If I had a second chance at this mishap the first thing I would check is "the source"! There was obviously a huge voltage drop between the battery and the TCU.
I already mentioned that the ground and battery feed are fed directly to the TCU using #10 wiring and then they break down to #18 wires running into the interface module and TCU.<br />
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Step one is check for voltage drop... hindsight is easy after the fact but the time we spent along with the dealer on this issue was excessive. The problem always gets fixed it's a matter of how many hours it takes.
In the video you can see the dash and interior layout.<br />
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The fit and finish was very good on these models. We've had Cummins power as well in these buses .... official model >>>> ER Saf T Liner. They handled nicely and gave us a lot of miles without trouble. However the Cat 3116 engines did have valve problems and required a few rebuilds. Normally our buses stick around our fleet for 12 to 15 years depending on the mileage.<br />
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If there is premature rust sometimes we retire them early considering the cost it would take to repair properly.
Thanks for hanging out...please leave a comment and/or share this post if you liked it. Until next time take'er cool :)
Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-89924556277429161622015-06-20T17:27:00.004-07:002015-06-20T17:29:37.958-07:00Cummins ISC Diesel Engine CAPS Failure<iframe allowfullscreen="" frameborder="0" height="281" mozallowfullscreen="" src="https://player.vimeo.com/video/98988274" webkitallowfullscreen="" width="500"></iframe> <br />
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<a href="https://vimeo.com/98988274">Cummins CAPS Assembly Repair</a> from <a href="https://vimeo.com/user23325240">John Whelan</a> on <a href="https://vimeo.com/">Vimeo</a>.<br />
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This Cummins ISC diesel engine is in a 1999 Thomas pusher school bus. The engine died suddenly and eventually we found the drive failed in the CAPS pump assembly. Luckily the fuel injection shop we deal with had a core in the back room. We got lucky because the replacement of the pump assembly is around 4,000 dollars.<br />
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Most of the ISC diesel engines in our fleet have required a new pump. What happens is multiple engine codes that don't go away. There's a lot going on in the CAPS assy. It develops and controls the high pressure fuel that is distributed at the right time to each injector.<br />
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Running at 250 horsepower they are a great engine well suited for a school bus fleet. Other failures were injectors but not very often. The crank and cam sensors act up along with fuel leaks at the electric fuel pump. Our fleet only has 3 of these buses left and they are standing up very well for being thirteen years old.<br />
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The fuel pressure sensor in the CAPS accumulator was a regular failure through the years. Cummins did come up with a update on the sensor along with a replacement harness. It only takes 10 minutes to replace the sensor. I personally think Cummins has always been the leader in medium duty diesel engines.<br />
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I was an International DT466 fan for years until the emission and electronic version came around. Mechanical fuel injection can not keep up to emission guidelines and the old DT had to be scrapped. They were the best fleet diesel back in it's day but sometimes good things have to come to an end.<br />
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At present Cummins has the ISB which runs on DEF (diesel exhaust fluid) and besides the extra maintenance they are the most reliable engines in our fleet. They run seamlessly with the Allison automatic transmissions and the operators really like them for power and we like them for reliability.<br />
Please comment and share this post and thanks for visiting my blog.<br />
<br />Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-25980469200508174502015-06-18T15:24:00.001-07:002015-07-23T19:42:42.241-07:00Cat 3116 Rear Seal Installer For Sale<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXd1_apzCR5f5Am6DaVWcU3pGbQaL881V-Ym-56AntbTG8KmgEM_6F6qv7v87OJaYNYpcJ33TWIq61dihF9AgFK6WTZQlI9-2sRIVTSGCAYVzuDWso6YFslPq-crQvng8WjU5_/s1600/rear+seal+tool.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXd1_apzCR5f5Am6DaVWcU3pGbQaL881V-Ym-56AntbTG8KmgEM_6F6qv7v87OJaYNYpcJ33TWIq61dihF9AgFK6WTZQlI9-2sRIVTSGCAYVzuDWso6YFslPq-crQvng8WjU5_/s320/rear+seal+tool.jpg" width="320" /></a></div>
<b><span style="color: red; font-size: large;">This seal tool has been sold</span></b><span style="color: red;"><b>....thank you for your inquiries.</b></span> If you're doing repairs on Cat 3116 diesel engines here's a rear seal installer tool that we're looking to sell. In a previous post I mentioned that we no longer have 3116 engines in our fleet. This tool does it all if you have to replace the seal.<br />
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I got a new price from CAT and they said $500.00 Canadian funds<br />
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This tool is used so we will sell it for $125.00 U.S. + Freight<br />
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Leave a comment below with your contact information.<br />
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I have a post on this blog that demonstrates how this tool works. Check it out <b><a href="http://schoolbusmechanic.blogspot.ca/search?q=cat+3116+rear+seal" target="_blank">HERE </a></b><br />
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<br />Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com1tag:blogger.com,1999:blog-18449820.post-63862467794875327142015-06-17T17:03:00.000-07:002015-06-17T17:07:38.866-07:00Cat 3116 Fuel Solenoid For Sale<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwcaG9OXCI9RVOolLFgnDWCH805J7hOEw9PbhpjNSQ9Z8bzpe7xbP228bQt0vQTG4785Kx973xAmI2pxgswUDcFxkYLlVTEmHT0-phQGvpP9ZMvLsdYhaPcNtD3jmkh0WTcd-L/s1600/cat3116.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwcaG9OXCI9RVOolLFgnDWCH805J7hOEw9PbhpjNSQ9Z8bzpe7xbP228bQt0vQTG4785Kx973xAmI2pxgswUDcFxkYLlVTEmHT0-phQGvpP9ZMvLsdYhaPcNtD3jmkh0WTcd-L/s320/cat3116.jpg" width="320" /></a></div>
Since we sold all of our Cat 3116 engines a couple of years ago we have no need for Cat parts.<br />
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This fuel solenoid is new...never used out of the box. The last price that we had on it was $355.00 Canadian.<br />
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We will sell if for $100.00 U.S. plus freight. Contact me in the comments section below and let me know if you're interested along with your email address. I'll give the first response priority.<br />
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These solenoids are activated with the key on and the winding pulls in the piston to turn fuel linkage on in the governor housing. They screw in and are sealed by an o-ring.<br />
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Here is more information regarding the <a href="http://schoolbusmechanic.blogspot.ca/search?q=cat+3116+fuel+solenoid" target="_blank"><b>Cat 3116 solenoid</b></a> on a previous post. There you will find torque specs and operational details.<br />
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Check out this link which leads to all of the <a href="http://schoolbusmechanic.blogspot.ca/search?q=cat+3116" target="_blank"><b>Cat 3116</b></a> related posts on this blog.<br />
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Thanks for the visit ... please comment and share this post.<br />
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<br />Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-49623367395157390862015-06-16T23:18:00.000-07:002015-06-16T23:18:04.599-07:00Allison 3000 Automatic Transmission Turbine Sensor Replacement<iframe allowfullscreen="" frameborder="0" height="281" mozallowfullscreen="" src="https://player.vimeo.com/video/117029089" webkitallowfullscreen="" width="500"></iframe> <br />
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Allison 3000 Automatic Transmission Turbine Sensor Replacement requires removing the bottom module of the transmission using a transmission jack. The module weighs around 50 pounds so it's much easier to lower it down easily while feeding the harness through the access hole in the transmission housing.<br />
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The turbine sensor is internal and is easily replaced once the module is exposed. This code is not very common but it was plain as day when hooked up to Allison DOC software. You can view a graph while road testing and the turbine sensor communication dropped out while on the road. There are 3 sensors on the Allison 3000 models. The engine speed sensor, output speed sensor and turbine sensor.<br />
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All these sensors have to be working properly for the transmission to shift properly. They can be tested using an ohm meter. Depending on the ambient temperature the reading should be around 300 ohms. The video gives you an idea on what the module looks like when removed from the main body and where the turbine speed sensor is located.<br />
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The 3000 series are very durable and most of the problems were in the wiring. The plastic convoluted loom that the harness is wrapped in is deadly on the wiring insulation. Through time vibration causes the loom to rub on the wiring and eventually expose the copper wire to the atmosphere. Years ago we would run new wiring to a sensor because of the resistance caused by exposure to the elements.<br />
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The special wire was twisted and shielded that fixed a lot of communication problems, Using the Pro Link was the first tool available for troubleshooting. Now Allison Doc software is the only way to go. Also I have to give a plug to synthetic transmission oil which in the past I refused to accept because of the price.<br />
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Believe me it's well worth the extra cost. Our mechanical failures are non-existent since using synthetic oil. It lasts longer and does not break down in the heat. Our services are 3 years between oil changes. You can't beat that when in our case we're running 77 school buses.<br />
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Getting back to our turbine sensor code repair. When removing the module I want to point out that you need to remove the 32 fasteners by hand. The aluminum threads in the housing wear out..... especially the filter housing retaining bolts. It isn't a fun experience heli coiling the threads on these units. We have a Kent Moore tool jig to re-thread the holes which is the only way to do it. I use a speed wrench to remove and replace the bolts.<br />
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I hope you enjoy the video and please make a comment and share this post. Cheers! <br />
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<br />Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-71181069821433630952015-06-08T23:21:00.001-07:002015-06-08T23:21:54.735-07:00Mechanics and Corrosion <div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4DH0-uT34TIrDXbFszXqng_WxpeV6G068f61m8P1TnYk6K9VvNzzRdQQDvojC2ybCVNxF1pCqMRM0xc437hA7wkKyHi9moslnEK-o0q-IW4tF9yr7DDe2hh-apApmVfoEk4Cl/s1600/wrg+corrosion.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="189" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4DH0-uT34TIrDXbFszXqng_WxpeV6G068f61m8P1TnYk6K9VvNzzRdQQDvojC2ybCVNxF1pCqMRM0xc437hA7wkKyHi9moslnEK-o0q-IW4tF9yr7DDe2hh-apApmVfoEk4Cl/s320/wrg+corrosion.jpg" width="320" /></a></div>
The most difficult job when finding an electrical fault is when corrosion is involved. It's hiding somewhere in a connector or poking through the wiring insulation. <br />
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So what is the best way to troubleshoot corrosion in the electrical system? One way is to search and destroy the problem by opening the loom and exposing the green stuff but that is frustrating and takes a lot of time. However it's necessary to make a proper repair.<br />
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Another method (when you know which circuit is faulty) would be to check for voltage drop in the circuit that is not functioning. If you can hook up a volt meter at each end of the circuit and see if there is a loss of voltage when the circuit is energized then you can be assured it's a bad wire. Checking the resistance is another check that works. <br />
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In our shop we've been using a load on the wiring circuit in question. A regular light bulb (non LED) hooked up to the one end of the wire will tell you if there is a lack of current when the light is dim after energizing with battery power. The wiring is either corroded or frayed restricting current flow.<br />
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If you have money to spend on tools you could use "diamond logic builder" software for International trucks to see the circuits working in a graphic form on a laptop. You can click on a circuit and actually see if the load is getting battery power. The pin outs on all the connectors are at your fingertips. I've used this software and it's a great tool to have compared to digging through wiring harnesses with a hope and a prayer. Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com2tag:blogger.com,1999:blog-18449820.post-23315030821699971902015-02-01T15:51:00.002-08:002015-04-01T21:34:49.748-07:00Mercedes MBE 900 Diesel Engine Emission Code dpf out of range high<div style="text-align: center;">
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This code we're working on is a "DPF out of range high" on a Mercedes MBE 900 Diesel Engine. What triggers this code is a pressure differential between the inlet and outlet of the diesel particulate filter cartridge. In the video you can see the clamps on the outside of the muffler that can be removed allowing the cartridge to be removed for cleaning.<br />
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There are several shops in town that will do a cleaning of these cartridges. It's a two step process depending on how badly the blockage is. When using detroit diesel diagnostic software you can go in and see what range the filter is running at. It's 0 to 4 range with four being severe. Once the engine control module detects blockage it will run a regen while the engine is in service.<br />
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In a perfect world that's all the emission system would need to do running regenerations to keep operating without any trouble. The DPF amber dash light illuminates when the regen process is taking place. There is no worries if it flashes on and off indicating a normal function instigated by the engine on board computer.<br />
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Mercedes calls the engine computer an MCM (motor control module).
When hooked up with the laptop and software the tech can find the code and click on the "troubleshoot code" button at the bottom of the screen. This directs you to a step by step process to check one thing at a time then moving on to the next step. In this case the outlet braided pressure hose that reads outlet exhaust pressure of the filter cartridge has to be removed and tested for blockage.<br />
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It could be blocked with soot and ash build up and the best thing to do is replace it. This fault was cured replacing the hose. If it did not help the filter cartridge may be plugged up so a forced regen is a good idea. Eventually over time the filter cartridge needs to be serviced or replaced. Mercedes recommends servicing at 125,000 km or 75,000 miles.<br />
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We have 18 of these diesel engines in our fleet and have a good deal of experience which is your basic "hands on" experience that is of course the best teacher.
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Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-59937656095947619672015-01-24T23:06:00.001-08:002015-02-01T16:33:57.065-08:00Espar Diesel Heater New Impact Switch and Harness Replaces Original Push Button Version<div style="text-align: center;">
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All of our Navistar conventional school buses come with the Espar Hydronic 5 (E-Guardian) diesel coolant heater. The impact switches that came with the heaters are very sensitive and would pop when ever the bus went over rough roads.<br />
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We did a partial fix by using a hole saw and reaching in to the heater housing and resetting the switch. This was a hassle but necessary to keep them operating. Low and behold the engineers at Espar came out with a new impact switch and harness that does not cut out over rough road. <br />
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The part numbers for this unit are below. There are 3 harness options and just one impact switch. Impact switch number: 252800705050OZ . The harness that fits the Hydronic 5 we have is 25280070100200OZ. The International dealer can get you the parts or anyone who has dealer status for Espar.<br />
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A great advantage to getting Espar heaters is the software is free to download. Go to the <a href="http://www.espar.com/" target="_blank"><b>Espar website</b></a> to get the software. The heater comes on in cycles starting with the blower and fuel pump then the electrode to start the burner.<br />
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The fuel used is minimal about 1/2 a cup of diesel per hour. With anti idling laws around schools these heaters preheat the buses long enough to get the interior temperature up fast. They operate for 2 hours at a time during each cycle. The faster a diesel engine can warm up saves fuel due to less warm up time in the morning.<br />
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If you are interested in these heaters it's possible to install them after factory with a complete install kit. You just have to get a fuel feed from the tank and hook up the coolant plumbing and electrical. Our shop installed a Webasto heating system on an International conventional bus because it was parked out of town and we wanted more assurance that it was going to start in cold weather.<br />
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Thanks for viewing this page. Please comment and feel free to share this post.<br />
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<b><span style="font-size: large;"><i style="background-color: yellow;">Below is a video I did on setting the 7 day timer on an Espar
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Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com0tag:blogger.com,1999:blog-18449820.post-46366759409623218662015-01-16T23:43:00.002-08:002015-01-25T10:18:32.010-08:00Allison 3000 Series Automatic Transmission Turbine Sensor Code Repair <div style="text-align: center;">
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The Allison 3000 series automatic transmission or the older label "MD3060" in my opinion is an excellent design. The modules come off one at a time and they are really quite easy to work on. You need the right tools and manuals of course but gone are the days of balls, springs and extra assembly parts that were common with older auto transmissions. </div>
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The photo below reveals the turbine sensor which is internal. The bottom of these transmissions have an aluminum cast unit called the control module. It has all of the solenoids and valve body that controls shifting. The code we had was a turbine sensor which stopped working only at certain times during a bus run. The turbine sensor being a winding which delivers the turbine speed signal to the transmission control unit was failing when the oil temperature got to a certain level. </div>
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<b><i><span style="background-color: yellow; font-size: large;">Click on Each Photo to Enlarge</span></i></b></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzzBR3SFCadPbF6dtU-bkmrD_4UeIYDdsA1BA3HFtTh_SznxI3FZH3nkVfpWobmHiAYEPYjYWSs0SJPbtomSp1pBt5tys0AyUOlIB9_xAGS-4YuuWS7qj7ZAZFxdOYkqCOzo31/s1600/20150115_110316.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzzBR3SFCadPbF6dtU-bkmrD_4UeIYDdsA1BA3HFtTh_SznxI3FZH3nkVfpWobmHiAYEPYjYWSs0SJPbtomSp1pBt5tys0AyUOlIB9_xAGS-4YuuWS7qj7ZAZFxdOYkqCOzo31/s1600/20150115_110316.jpg" height="300" width="400" /></a></div>
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Using the Allison DOC software we were able to go on a road test and observe the turbine speed sensor and exactly what it was doing. The graph you see below in the photo show the activity of the output speed, engine speed and turbine sensors. These three signals are what the TCU reads to send the right information to the control module during operation for a proper shift at the right time and in the correct range.</div>
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Looking at the laptop image (click on the image to see more detail) you can see how great it is to be able to watch what the components are doing which makes it really easy to troubleshoot. What happened eventually when the transmission temperature got to around 140 degrees the turbine sensor flat lined on the graph reading causing the shifting to fail. At that time it was confirmed that the turbine speed sensor needed to be replaced and the labour to re and re the control module would not be wasted.</div>
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The control module is around 50 pounds so you need a tranny jack for sure. There are 2 dowels that line up the module to the main case and it's a bit of a fight prying the module down on to the jack. With some care it can be done including the removal of the wiring harness which slips through the access hole in the transmission case.</div>
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Once the sensor was replaced along with the necessary gaskets and seals the module was reassembled with new filters and sump suction filter (internal). The synthetic oil was added then running checks were performed. The road test was a success and the bus went back into service. Synthetic ATF oil is worth every penny in my book with anti foaming and heat resistant properties far superior than standard oils.</div>
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<b>Valve body and shifting solenoids from the control module<span style="font-size: large;"> </span></b><br />
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<b>Here is a link to the Mechanic's Tips Handbook in pdf form. It has very good general information with torque specs for servicing and other useful tips. </b></div>
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<b><a href="http://www.utxchange.com/pdfs/MechanicsTips/MT2159EN.pdf" target="_blank">Allison Transmissions Mechanic's Handbook</a></b></div>
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Anonymoushttp://www.blogger.com/profile/01517188475250181833noreply@blogger.com3