School bus wont move after sitting over winter

[ateymura]

Hi All,

Ok. Here it goes. I am new to here and school buses.

I have a 2006 international with dt466e and allison 2500pts, hydraulic wabco disk brakes on all 4 corners. 72 passenger. Got it last fall it was moving just fine... Drove it to my place and started working on stripping the insides.... Last thing i did to the bus before closing shop in winter was to paint it. At that point the bus was still moving.

It sat untouched all winter from about mid October to about end of March then when i went on to work on it again... It started fine after charging the batteries. One out of three batteries was dead (replaced now) but still does not really hold charge that well... Probably need to replace the other two as well.

Anyhow... It started but wont move.... I have vrawled under the bus the cable (going to a big drum at the end of driveshat in front of rear axel) for the parking brake seems to move when the parking brake is being disengaged from inside cabin. When i put the bus in revers and rev it up the bus seems to rock from left to right as if some torque is being applied.. Not sure 100%. When i put it into drive and rev it up it seems to rock side to side a bit less.

So i am not sure if the brakes are stuck or is the transmission not really engaging? And not sure what to really look for. Any help/advise would be really appreciated.

By the way where are the diagnostic ports on the busses? I am fairly handy when it comes to passenger cars but pretty clueless with the bus.

[magnakansas]

Check and verify correct fluid level for transmission. This is done with engine running.

William

[ol trunt]

Since the bus rocks side to side I'd guess the trans is working. I've had brake shoes rust to the brake drum on several old cars that sat out in damp weather for a long time. As a cheap and easy fix, flood the inside of the brake drum with a garden hose to soak up the rust. Do it a couple of times over night and then fire up the bus and shift it back and forth between drive and reverse (like you were stuck in snow) and see if the brake shoes release. YMMV
Jack

[Samarath]

Originally Posted by ateymura

By the way where are the diagnostic ports on the busses? I am fairly handy when it comes to passenger cars but pretty clueless with the bus.

Looking under the dash to the right side of the radio should be your comm port. Mine Is a round 9pin in the 2007 IC ce200.

[ateymura]

Thanks for the replies.

Originally Posted by magnakansas

Check and verify correct fluid level for transmission. This is done with engine running.

William

Checked the transmission fluid level with engine idling (after 10 -15 minutes of idling). While i dont think the transmission was really hot yet, the fluid level was only at the bottom of cold mark...

I guess needs a fluid change... Was looking online for a spin on filter... (currently it has a donaldson P550606 on it) what is the difference between black and red (29539579) filters?... Do i need to drop the pan and change the filter inside as well?

I was looking for some signs of where and why the fluid would be low (a leak?) Found a couple of damp spots on the transmission. One on/arround inspection hole on the bellhousing and a also one near the shift lever (on the driver side closer to the back of the transmission). No signs of dripping on the ground though.

Originally Posted by ol trunt

Since the bus rocks side to side I'd guess the trans is working. I've had brake shoes rust to the brake drum on several old cars that sat out in damp weather for a long time. As a cheap and easy fix, flood the inside of the brake drum with a garden hose to soak up the rust. Do it a couple of times over night and then fire up the bus and shift it back and forth between drive and reverse (like you were stuck in snow) and see if the brake shoes release. YMMV
Jack

It has disk brakes in the back so soaking the pads probably wont work as water will just drip out?? I can try to remove the calipers maybe and see if the pads are stuck? Done dosens of brake jobs on cars are the buses much harder?

Originally Posted by Samarath

Looking under the dash to the right side of the radio should be your comm port. Mine Is a round 9pin in the 2007 IC ce200.

Thanks willl look for the comm port tomorrow.

[Dbacks2k4]

Originally Posted by ateymura

By the way where are the diagnostic ports on the busses? I am fairly handy when it comes to passenger cars but pretty clueless with the bus.

Conventional, front-engine, or rear-engine configuration?

On a 2006 conventional the diagnostics port will be on the right side of the drivers seat under the dash, under where the stereo is. On an FE or RE, left side of the drivers seat under the dash (under the windshild wiper controls). An RE will also have a diagnostics port in the engine compartment, passenger side, black box on the rear wall where the fuses are. It's a 9-pin round connector. Servicemaxx is the best diagnostic tool, free, but requires a Nexiq usblink adapter or a chinese knockoff.

You've got a bit of a rare gem, I think. Almost every *300 bus with the 466e in it I've seen have been air brakes. Hydraulic brakes were much more common on the *200 series VT365s. Could be just the brakes rusted, but if your engine is having issues putting out power that could cause the non-movement, especially on a non-concrete or sloped surface. My bus with a failed EGR valve in it right now (I've got same engine and year you do) suffers from lack of power and stalls if you put too much load on it... but that doesn't sound like the symptoms you're describing. FYI - EGR doesn't have a sensor in it on that engine, so no codes for that.

Cheers,
Kevin

[BamaBus]

Originally Posted by ateymura

(going to a big drum at the end of driveshat in front of rear axel) for the parking brake seems to move when the parking brake is being disengaged from inside cabin. When i put the bus in revers and rev it up the bus seems to rock from left to right as if some torque is being applied.. Not sure 100%. When i put it into drive and rev it up it seems to rock side to side a bit less.

So i am not sure if the brakes are stuck or is the transmission not really engaging? And not sure what to really look for. Any help/advise would be really appreciated.

If this driveline brake is a drum setup then the shoes on it could be stuck.

Unless you are lucky and have a helper I would use a cell phone to video driveshaft to determine if there is any movement.

Brake fluid level good?

[Oldyeller]

I have an '04 IC CE200 with hydraulic brakes. I would be inclined to have a better look at the parking brake before I assumed anything else. If you can safely (that means chocked wheels) get under the bus with a helper inside have them release the parking brake lever (it is a manual parking brake right?) and see if the shoes move away from the drum (on the drive shaft) at all.

I doubt if the problem is related to trans fluid level. If you lost enough trans fluid over the winter I'd expect there would be a significant puddle/spot on the floor/ground. It was moving when parked and now, after X months doesn't move. Seems more reasonable that it's the brakes and specifically the parking brake which is entirely mechanical. Also you can actually see the shoes inside the parking brake drum so it should be easy to see if there is any movement when the parking brake lever is set and released.

Please be sure to tell us what the problem is/was when you figure it out. It's always interesting to hear how these things turn out.

[ateymura]

Ok. Just double checked. Brake fluid level ok. It is a front engine (i knew that part haha) CE 300.

I will get under the bus in the evening after work to see if parking brake shoes are visible at all, but from what i remember the drum is pretty solid... No inspection holes. It is not a mechanical parking brake. I mean at the end of the day yes you have a cable moving the shoes... But from inside the cabin it is a yellow knob that you pull to set the brake and push to release. Also, if i open the ignotion and let the HCU build up pressure and then release the parking brake without starting the engine.. I can hear movement in the back of the bus... But i am not sure if it is just the cable going back and forth or do the shoes move too.

[Oldyeller]

Originally Posted by ateymura

Ok. Just double checked. Brake fluid level ok. It is a front engine (i knew that part haha) CE 300.

I will get under the bus in the evening after work to see if parking brake shoes are visible at all, but from what i remember the drum is pretty solid... No inspection holes. It is not a mechanical parking brake. I mean at the end of the day yes you have a cable moving the shoes... But from inside the cabin it is a yellow knob that you pull to set the brake and push to release. Also, if i open the ignotion and let the HCU build up pressure and then release the parking brake without starting the engine.. I can hear movement in the back of the bus... But i am not sure if it is just the cable going back and forth or do the shoes move too.

From your description of the parking brake initially I thought you had a manual one. If it's not manual then it's not like mine. If you CAN see the shoes inside the drum you should be able to tell if it's releasing. I think there was another thread recently in which someone was dealing with the same kind of parking brake not releasing. It'll be interesting to see if you're dealing with the same issue.

[Don in E Texas]

I'm guessing you have air brakes. Is the pressure gage on you dash indicating the proper pressure? Is the air dryer valve opening/closing to maintain proper air pressure (you should hear when the valve opens and releases air) - I'm sure you have heard this noise in 'big rigs'. For your safety - and all others around you - make sure you fully understand how air brakes work. Unlike hydraulic brakes, if no air pressure: you have FULL brakes (hydraulic brakes - no fluid - no brakes). Yes, disk brakes are available on air brake vehicles. Lots of You Tube instruction videos available that might be of help to you. Also on another point -- what are your State drivers license requirements for your bus? Many States require at least a Class B license (over 26,000 pounds GVWR). If you take a drivers exam in your bus, the inspector will request you do an Air Brake Test. Stuff you need to know. That was the first question the examiner asked me when I took my Class A license many years ago. Don't think that has changed.

[ateymura]

I have hydraulic disk bakes on the bus by WABCO. If I knew how to post pictures on here I would.

[ewo1]

Originally Posted by ateymura

Hi All,

Ok. Here it goes. I am new to here and school buses.

I have a 2006 international with dt466e and allison 2500pts, hydraulic wabco disk brakes on all 4 corners. 72 passenger. Got it last fall it was moving just fine... Drove it to my place and started working on stripping the insides.... Last thing i did to the bus before closing shop in winter was to paint it. At that point the bus was still moving.

It sat untouched all winter from about mid October to about end of March then when i went on to work on it again... It started fine after charging the batteries. One out of three batteries was dead (replaced now) but still does not really hold charge that well... Probably need to replace the other two as well.

Anyhow... It started but wont move.... I have vrawled under the bus the cable (going to a big drum at the end of driveshat in front of rear axel) for the parking brake seems to move when the parking brake is being disengaged from inside cabin. When i put the bus in revers and rev it up the bus seems to rock from left to right as if some torque is being applied.. Not sure 100%. When i put it into drive and rev it up it seems to rock side to side a bit less.

So i am not sure if the brakes are stuck or is the transmission not really engaging? And not sure what to really look for. Any help/advise would be really appreciated.

By the way where are the diagnostic ports on the busses? I am fairly handy when it comes to passenger cars but pretty clueless with the bus.

Here is a Wabco Maintenance manual. Maybe you can find some answers there ?

File too big to upload so here is the link instead.

[Samarath]

If no lights are on at the dash, and there are no faults, then the wabco system should be okay. If it is like my bus, it is a SAHR parking brake (spring applied hydraulic release) and it should be pretty insistent about informing you if there is anything wrong with it.

The manual that wabco referred to me was mm-0401 and it was very comprehensive, however, other than installing the cable to the PB and messing with the PB valve on the HCU itself, Wabco doesn't actually offer support.

If you do have any brake related faults, your PB will not release. There are also many posts about various safety interlocks that may be worth reading. These guys have a lot of knowledge, and the only reason I chime in is because I just did a wabco HCU replacement. In my case, the previous owner cut the PB cable and so when my brakes failed, there was no backup plan. We rolled down the mountain until the mountain gave us a place to stop with its contours.

Are there any brake related lights on your dash?

[ateymura]

No dash lights. Sorry to hear about your adventure with the brakes.. the park cable itself definitely moves, not sure about the shoes in the drum. I will add some trans fluid first as suggested earlier... then try to remove the brake calipers to make sure they are not stuck. at least that's the plan for now.

[Dbacks2k4]

Originally Posted by ateymura

I have hydraulic disk bakes on the bus by WABCO. If I knew how to post pictures on here I would.

With a yellow knob and a wabco that sounds like an air over hydraulic parking brake. Are you building up air pressure? Could be a bad compressor, an air leak, or an air dryer cartridge in need of replacement

[ateymura]

Originally Posted by Dbacks2k4

With a yellow knob and a wabco that sounds like an air over hydraulic parking brake. Are you building up air pressure? Could be a bad compressor, an air leak, or an air dryer cartridge in need of replacement

I have exactly whats shown in the manual shared by

Originally Posted by ewo1

Here is a Wabco Maintenance manual. Maybe you can find some answers there ?

File too big to upload so here is the link instead.

it does build up pressure but from my rudimentary understanding of the system it is building up hydraulic pressure. has two electric pumps and two chambers... (for safety and redundancy) to provide braking even if engine stalls.

[ateymura]

here are some images of the brake setup on the bus. calipers with pads, rotors, parking brake drum on the drive-shaft, transmission identification plate and also of the two oily places; one near bottom of the bell-housing and one near the shift lever on the transmission. if someone can tell me how serious these are or if it is a quick gasket change here and there.. that would be useful.

[BamaBus]

Thanks for the pics. The chances of a rusted or a stuck caliper slide has greatly improved. One could only hope so after reviewing the Wabco info and reading Wabco threads here along with other sites.
Use the big hammer treatment on the driveline parking brake to possibly free up the shoes. I still wonder if you are getting any driveshaft movement when in gear. I don't think you would get the torque movement if your transmission was slipping.

[ewo1]

Originally Posted by ateymura

here are some images of the brake setup on the bus. calipers with pads, rotors, parking brake drum on the drive-shaft, transmission identification plate and also of the two oily places; one near bottom of the bell-housing and one near the shift lever on the transmission. if someone can tell me how serious these are or if it is a quick gasket change here and there.. that would be useful.

After looking at your pictures I would disconnect the driveshaft at that driveline brake drum, open it up, inspect clean and lube. that should be an easy job. I would even consider some light rust treatment and paint.

Then I would take a hammer and tap on the calipers and if possible, use a drift to tap on the pads themselves just in case they did freeze to the rotors.

Once you are confident that things are free, see if the bus then moves.

Me personally, that's what I would do first. consider it preventative maintenance.