Brakes Not Releasing

[Golden_Otto_Bus]

Hi all,

So I have a 2003 Blue bird, with air brakes and suspension, TC 1000/2000 model.

I left the house today and got around the corner and the brakes locked up. The air pressure was fine. I got out and heard air coming from the rear driver's side air brake can ( believe that is what it is called). Mechanics came and fixed that and they thought it would then allow the air to stop leaking thru that and release the brakes. No luck.
I drove it home a short ways by pressing a "brk ovrd" switch witch temporarily released the brakes.

Some sort of safety switch triggering the system so it applies the brakes? I was working on the air hydraulic door that morning. Seems like it doesn't close quite as much but not positive. Other possibilities? Any help would be greatly appreciated!

Cheers, J

[Golden_Otto_Bus]

Adding more here: When in this condition I can't apply gas when in drive or reverse, brake light stays on and the bus won't move or even recognize my foot on the accelerator.

[jimmythomas]

Your bus thinks the door is open. Repair the wiring / switch.
Good Luck!

[Simplicity]

It could be related to the door, yet in general a door not closed completely would generally just sound a buzzer. Hell, yesterday I drove a brand new bus and forgot to hit the emergency air release switch. I drove that bus with the doors half open onto the freeway. Schools don't want buses locking up breaks for just any reason, and forgetting to close the service door isn't a good enough reason.

Having low air pressure is a good reason, and since you had a leak in the rear "can", it may be that it set a mechanical break lock, which has to then be mechanically released?

https://www.youtube.com/watch?v=Ef06PdkIgaE

https://www.youtube.com/watch?v=f9fLf4UUIQE

These may help get you further.

[Golden_Otto_Bus]

Thanks. I ended up contacting Bryson Sales & Service of Wa (877-882-7976) and spoke with Kevin. He knew exactly the issue! Yes the emergency interlock system was acting up likely due to a door switch/alarm trip. I went under the bus and eliminated the solenoid that activates that system. Now it has released the brakes and lets the accelerator work. We plan to take the bus to their shop in Everett when we get there in a few weeks to check over the bus and the air/brake system.

[Golden_Otto_Bus]

Thanks for the great info. I will look through those vides, thanks for the links!
The bluebird bus American does actully activate the brakes when a door alarm is triggered whereas most buses just don't let you start them as far as I know. I could be totally off base though... ;)

[magnakansas]

really happy for you that you found your answer.

bon voyage

william

[Simplicity]

So the poster who suggested it was related to the door was right. That's cool! I realize now that my example of driving with the door open I had the emergency door release switch activated.

So, I'm wondering if you reconnected the solenoid and flipped your emergency door release switch, if that would allow you to proceed.

The reason I'm interested in the test, is that if for any reason this ever happens again, you at least know that you could move the bus even if the door service door wasn't completely secured.

It's always good to know work around!

Please follow up with what the mechanics find about your system so we can all learn from that. Glad it's working!

[cadillackid]

you guys got it.. some districts require the brakes to lock any time the door is open.. the city of columbus has that system on their newer school busses.. when the reds come on and door switch calls for open door the parking brake applies.. this only happens below a certain speed.. thus a kid in the back cant open the emergency door and grenade the air brakes..

[Golden_Otto_Bus]

One more update here. The next day we went to go for a longer test drive and the accelerator stopped responding again. It would work when the 'brk ovrd' button was pushed. Talked to the experts and they suggested I also disconnect the brk ovrd button and that worked. Made a ten hour journey the next day with no issues (besides the slight breeze in Wyoming of 65+ mph!).
We did not find the specific door emergency switch that caused the issue. Assumed the front door was the culprit but never quite sure. When I released the manual lever on the front door (emergency) it did not change anything at that point.

[o1marc]

Brake override switch—Optional.The brake interlock system is a safety feature. The system does not allow the vehicle to be moved with the doors ajar. This switch over-rides the system enabling the vehicle to be moved while the doors are in the open position. NOTE: For emergency purposes only.

[cadillackid]

Ha! And here I purposely drive my superior with the door open on hot days!