Won an LMTV M1081 out of Ft. Bragg

[Suprman]

Its possible the dash valve has air leaking thru it. Does it look recently replaced?

 

[jjb]

Its possible the dash valve has air leaking thru it. Does it look recently replaced?

It looks like it was removed recently. Can't tell if it's new. It releases air when I pull it out

 

[Suprman]

Do the rear brakes engage when you are driving and step on the brake pedal?

 

[jjb]

Do the rear brakes engage when you are driving and step on the brake pedal?

I believe so but need to verify.

 

[Suprman]

If the rear brakes work with the pedal but not with the parking brake control then I would replace the parking brake control. Air could be getting by. If the rear brakes are not engaging with the brake pedal either then I think something may be plumbed wrong. Recently replaced parts are a good place to look for switched connections.

 

[Lmtv772]

What I would start with are the known bad valves namely the 3 valves under the driver side cab. I had one truck that bypassed air through the parking valve, while there were leaks through out the system. Once I replaced the valves the park brake stopped bypassing air.

 

[jjb]

What I would start with are the known bad valves namely the 3 valves under the driver side cab. I had one truck that bypassed air through the parking valve, while there were leaks through out the system. Once I replaced the valves the park brake stopped bypassing air.

I have one bad check valve for sure on the rear cross member. I need the check the others.

 

[jjb]

I will replace the one first and see if it works. That one looks like is supplies the relay valve.

 

[jjb]

It turned out to be the Park control valve being hooked up wrong. My first clue should have been that the park control and trailer supply valves were in the opposite locations of what the TM's show (Park control on top of the trailer supply).

I spent every night this week looking at the TM's for troubleshooting steps and how all of the air lines are routed. 2 lines were switched. Switching them back fixed all of my issues. The parking brakes not working, the brake pedal not returning and the air/hydraulic system not functioning). The delivery port was connected to the treadle vent.

Thanks for all of your help.

 

[NDT]

That will be the second GP FMTV found to have crossed hoses due to mistakes made by someone within the military! "Sarge, this one cannot be fixed, send it to DRMO."

 

[jjb]

That will be the second GP FMTV found to have crossed hoses due to mistakes made by someone within the military! "Sarge, this one cannot be fixed, send it to DRMO."

That was exactly what I was thinking when I figured out they were crossed. I found a few other things they replaced probably trying to fix the issue. Then they ultimately gave up and sent it to DRMO.

Their loss is my gain I guess