Quote:
Originally Posted by jeet
I have a century class, lately its leaking air big time (from blue line behind bunk ), every time i step on brake padle ( bob tailing ). Air even leaks when yellow and red dash buttons are pulled out and I step on brake padle. Any idea what might be causing it... Thanks
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Yellow dash valve should have nothing to do with it, BUT, it sure sounds like a faulty Red Dash Valve.
Of course, they are not a single unit anymore, they are a module. so If you swap one out, then the other goes with it.
There is no air to the Tractor Protection Valve UNTIL you push in the red dash valve. Until then, it works like a seal. Once you put air to the Supply (red) then it moves a slider which enables air to come out of the service (Blue) when you make a brake application.
Could be the TP, but more than likeley it is the Dash valve.
Do you hold the trailer in RED, when you dynamite the tractor Yellow, and then pull the Red to set the trailer brakes. If you do, there is a really good chance that is what caused it.
Proper procedure for setting your parking brakes, Tractor with Trailer attached is as follows
Pull yellow, red will almost always follow.
Even if you need Air in the trailer for some reason, you need to set Yellow (red follows) then push the red dash valve back in to release the parking brakes at that time.
I see it often where guys come in and hold their thumb on the Red button while they pull the Yellow button with the middle two index fingers, then pull the Red out.
I have module dash valve set in my shop that I use to show what happens when you do it. They eventually leak.
The manufacturers sent out notices years ago that it is not advisable to hold in Red, while you dynamite Yellow.