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ernst · (This post was last modified: 02-12-2014 07:05 by ernst.)

1) When I was disassembling the air tanks from my 1998 TCFE4000 I noticed a red 120 A circuit breaker(?) between the tanks and the left front wheel. The button can be seen in the attached picture (top).
Anyone knows what it is for?

2) In the switch panel on the driver's left hand side is a small black pushbutton marked BRK OVERR. Pushing it in different conditions doesn't make any difference.
What is it and when do I need it?

davidbrady · 02-12-2014, 13:41

Hi Ernst,

The Brake Override switch is to disable the brake interlock feature. An example would be if you had a lift on the bus to wheel in passengers, the interlock would prevent the brakes from releasing while the lift is deployed. There may be other doors that when open enable the interlock. The Brake Override disables the interlock feature allowing you to move the vehicle.

I don't know what the red button by the air tanks does. I can imagine that in the case of a roll over perhaps the red button disables an air door lock but I'm only speculating.

***patticake*** · 02-12-2014, 20:06

I think the red button enables the driver's ejection seat Cool

mhughes01 · 02-13-2014, 04:51

(02-12-2014 20:06)patticake Wrote: I think the red button enables the driver's ejection seat

Careful, it's a homing device activator and activates a transporter to beam the Bluebird back to Georgia where it was made.

ernst · (This post was last modified: 02-13-2014 06:25 by ernst.)

I alway thought it would be better to have the handle to activate an ejection seat close-by, rather than having to crawl under the bus. Just in case....

The homing device could come handy. At least, if it takes passengers as well.

David,

Clear! I only don't know how the brake interlock feature in my bus would be activated. There is an air-operated front door, but I can drive away with an open door just like that. There used to be a box with a microswitch, a keylock, a relay and a buzzer on the rear window. One needed the same cylinder for locking the emergency window and for switching off the buzzer, so that one wouldn't drive with a locked emergency exit. I removed the box five years ago. And there are microswitches on the two emergency exits, which don't do a thing. Maybe any of those (used to) lock the brakes...?

From your description I understand it is safe to just forget about that button. Am I right?

oldmansax · 02-13-2014, 12:06

(02-13-2014 05:48)ernst Wrote: From your description I understand it is safe to just forget about that button. Am I right?

Any chance of tracing the wiring from the red buttoned breaker? If you can find out what it disconnects (protects) you may be able to discern what it does. It LOOKS like a main feed to the bus sub panels. Something that would trip if you have an accident that shorted out the main power supply. Since it is a manual reset and in a very inaccessible location, it was only meant to trip in extreme circumstances and required some amount of effort to reset it.

TOM

ernst · 02-14-2014, 06:02

That was my conclusion as well. Also because 120 Amps is quite a current. I wouldn't know what draws so much - apart from the starter which draws a lot more.
I'm not really in the mood to crawl under the bus right now (I lowered it after I finished with the brake tanks) in an unheated shed. Maybe next Summer...
I realise just now: the location of the red button is about halfway between the battery compartment and the outside fuse box....

davidbrady · (This post was last modified: 02-15-2014 19:10 by travelite.)

(02-13-2014 05:48)ernst Wrote: David,

Clear! I only don't know how the brake interlock feature in my bus would be activated. There is an air-operated front door, but I can drive away with an open door just like that. There used to be a box with a microswitch, a keylock, a relay and a buzzer on the rear window. One needed the same cylinder for locking the emergency window and for switching off the buzzer, so that one wouldn't drive with a locked emergency exit. I removed the box five years ago. And there are microswitches on the two emergency exits, which don't do a thing. Maybe any of those (used to) lock the brakes...?

From your description I understand it is safe to just forget about that button. Am I right?

I'd disregard the switch Ernst. On a Blue Bird it's not surprising to find switches that aren't active. The feature could have been removed by a previous owner or it may have been left out of the original Blue Bird Build Sheet with remnants like dash and micro-switches still in place. Attached is a pic of the typical Brake Interlock; number 75 is labeled VALVE ASSY, AIR BRAKE INTERLOCK. I believe the idea is that full brake air pressure is applied when a door is opened.

ernst · 02-15-2014, 19:19

Thanks. I think there is a similar device next to the air tanks, but it apparently is disabled. One concern less!