Emergency brake question

[freds]

This is probably a case of newbie operator head space.

The PO advised me to always put the emergency brake on when waiting at a light. A couple of times I have noted that the bus will roll with it on. Thinking it was a situation where at the time I engaged it I might not have had the brake petal down.

Is this how spring brakes work and operator head space on my part or does the emergency brake need adjusting?

Thanks
   

[DoubleEagle]

It might be overly cautious to put the emergency brake on at every light stop. If your air system is functioning properly, it is not necessary, and it will cause a delay in getting going. If the emergency brake is not holding, it is because the brake shoe clearance is not adjusted properly with the slack adjusters, and that will affect your braking whether moving or stopped. You need to check your brake adjustments at every wheel, soon. 

[buswarrior]

Strange advice.

Parking brake is used same as your car, for parking.

If it doesn't hold, you have serious problems, as it means the service brakes are likely just as useless on the drive axle, and all that is stopping you are the fronts and tags, maybe...

Parking and service all act on the same parts, so no brakes means no brakes.

Get this checked out ASAP by competent help.

Happy coaching!
Buswarrior

[freds]

The PO advised me to always put the emergency brake on when waiting at a light.

He mentioned that holding the brake pedal down for a long time would result in a loss of pressure, which I have seen no evidence of.

Also the bus air system holds air for about six to eight hours before it gets below minimum pressure.

[buswarrior]

Your PO is either stunned, or compensating for a serious air leak in the service brakes, which is also stunned...

Beware the rest of what you have been told, and the condition of everything on that coach.

PO are not usually selectively stunned, they are so broadly...

Happy coaching!
Buswarrior

[richard5933]

Sounds like two things are in order...

1) Verify that all brakes are properly adjusted and not worn past their useful life.

2) Check for air leaks and repair any found.

[blue_goose]

Check on how to do a DOT air brake test.  Do that and if it fails get it fixed.
Jack

[bevans6]

Does a 1980 Prevost have spring brakes?  It takes around 65 psi to release the spring that applies the E-brake with spring brakes, so applying the brake is the equivalent of a 65 psi brake application on the drive axle only.  Should firmly lock the brakes on that axle, the  equivalent of a firm application if the bus is rolling.  The only way that applying the brakes would result in air pressure loss with properly functioning system is if the brakes are applied and released repeatedly (AKA "fanning the brakes"). 

[chessie4905]

The best way to verify is to visually check rear brake chambers for two or three hoses.
For you coach owners that have two rear axles, if you have dd3's, are they usually on both rear axles, or just the drive axle?

[buswarrior]

DD3 vintage buses, will be mounted on the drive axle only.

With the newer buses being as heavy as they are, and the tag rated to carry as much weight as the steers, and the steers being way up 14-16k lbs...

I haven't been paying attention to which ones, but there are some newer ones out there with 2 axles worth of spring brakes to meet the braking standards.

Happy coaching!
Buswarrior

[freds]

The first thing that I did was put new tires on the bus (actually waited for AAA RV coverage to kick in first), before I drove it back from Oregon.

Didn't think to take pictures until they had already done one side of the bus. But here are a couple of pictures. Double chamber actuators are spring breaks right?