931 spring/maxie brake operation

[hot rod deuce]

Just picked up my 931,

im not asking what any of this stuff is, I know how a regular truck brake system works.

When you push the yellow button it will put air TO the chamber to take the brakes off, you pull the button out and it takes the air off, thus the springs put the brakes on.

Now, does it work this way on a 931 or is the hand brake what evacuates the chambers to but the spring/parking brakes on?
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[Rattlehead]

My 932 does not have a yellow knob, I believe they are both black. The one closest to the driver is to charge the trailer's air brake system. The one on the dash panel farther away is just to release the spring brakes with air pressure, only for testing and adjustment of the normal brakes.

When you apply the park brake, it automatically vents the spring brake pots so they will apply, as well as mechanically applying your park brake drum on the back of the t/case.

So in other words, you do not need to activate that dash button to take off, you just release the park brake.

 

[No.2Diesel]

Its right in the 939 series Ops manual:

Its called a...Spring Brake Release Control Valve

"This valve functions as an override when a failure in the air supply system (causing spring brakes to engage) occurs. When valve is manually pushed in, emergency air is supplied to the spring brake chambers. This releases the spring brakes, allowing vehicle movement."

 

[hot rod deuce]

Thanks guy, we loaded it up in the dark and I saw the bright yellow one first, its a regular truck one but it makes sense the way they plumb it. Im going to look for the other one at the next truck stop. Ill try to down load that manual on the way.


Thanks
again