Thursday, June 27, 2013

School Bus Garage Photos

I've been taking photos in our school bus garage since 2005 and didn't want them to go to waste so here is a short video with RANDOM pics. There's everything from instant snow chains to engine repair.

 2005...I remember it well, we still had mechanical diesel engines in the fleet. They were semi-retired as spare buses and just this year we are auctioning off our last mechanical engine equipped units (Cat 3116 models). The 3116 Cat gave us pretty good service but nothing stellar to speak of.

 I believe there were 4 engine rebuilds because of the exhaust valve dropping at a very bad moment. Usually the high heat pulling full load would cause the mishap. It was a lot of work since the block was solid without removable piston liners. The entire engine had to be removed from the chassis, stripped down and rebuilt from scratch. The rebuilt head ran about 1500 dollars Canadian, if the cylinder wall was scored then the block was sent to a machine shop which MUST know the repair steps when boring and re-sleeving these engines.

There is a special jig to be used to secure the block so it doesn't warp during the re-bore. It adds up to about 5K labor and parts. This of course is far less than buying a long block. The top end on the 3116 was the weakest part of the engine so valve adjustment is crucial. The engine operating temperature is a factor as well so they need TLC or they start to heat up over 200 degrees.

The engine fan in the pusher school buses were transversely mounted so it was hard to keep the temperature down especially in warmer months. We disabled the shutters (opened permanently) and installed an over riding dash switch to turn the engine fan on full which took some horsepower out of the engine. In the video you'll see the coolant sensor that runs the hydraulic fan solenoid.

When you unhook the sensor wire the fan runs full on. The dash switch we installed for the driver just caused a break in the circuit. It should also be mentioned that the cooling system also had to cool the transmission oil which could get up to 200 degrees. The radiator mounted sideways at the back of the bus had a hard time cooling especially when the bus was in 3rd gear with a full load climbing a hill in 80 degree weather. Thanks for viewing this post and I hope you liked the video.


Anonymous said...

An outstanding presentation John.
I have learned so much within the time of your presentation. In Toronto we send everything out, wish the administration could see beyond the present practice. A real mechanic is the way to go, parts changers are dime a dozen. Thanks again John.
Fred Lew-a-king

Nelson said...

Dear Sir.
my Name is Nelson Im a beginner Bus mechanic I was traktor and route trucks Wonderbread mechanic,im diagnosing and repairing a 2004 C-7 cat engine.engine run normal but after warming up engine,theres trouble,engine only cranking not running my boss order to replaced crank sensor and cam sensor all fuel filters are replace and air filter ,still same issue.I also checked all Fuses and wire are good, Im residing San Francisco, California,it takes Hour to get this BUS running,im working First student durnham Bus.
Sincerely yours
Nelson Borja

Clark said...


I bought a school bus and am redoing to start my own charter business. It was running great. Then this morning it wouldn't turn over, but the rear start would turn on the engine. The front start still wouldn't turn over. Any ideas what I should start doing.

scottsman said...
This comment has been removed by the author.
Wilson said...

I have a Allison wtec3 P/N 29538360 I lost light to R,N,D. I need a schematic to trace out problem to see where power comes from to unit.

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John Whelan said...

Thank you Fred for your comment!

Nelson... I would check the HEUI high pressure oil pump. It controls injection and may cause debris to enter the injector galleries and cause lots of trouble. Pull the dipstick and look for fine filings.

Clark, There is a hard wire circuit from the ignition to the rear if this is a pusher bus? It's usually a purple colored 12 guage wire. Just check your ignition switch and trace it back.

John Whelan said...

You will probably need to get a shift push button kit. They will fail sometimes.

scottsman said...

Took the push button shifter face off its box. Between the face and the circuit board is a semi whitish plastic. It's about 3/8"+ thick. I drilled a 3/16" hole about 1/4" deep hole. Top for Reverse, neutral on side, and drive on button. Mode side no. The other two yes the same way. Took a 5 mm red LED with pig tails and silcone around back side. Then slide into hole. Let it dry. Wired red to red and black to black to a light chord with disconnect on outside of box. Hook up to come on when key is on. Works great for day time and great for night. Same color as shift light.