Service air leak

[PureMayhem]

I have an air leak that I can hear in the intake pipe when the truck is shut off. I think I have tracked it down to the brake pedal valve. When I use my stethoscope I can hear air leaking though the bottom air line that goes in to the valve. I tried adjusting the pedal height but that did not work. I can apply a slight pressure to the brake, just enough to move the valve and the air seems to stop leaking. I have ABS. The system drains in about 30 minutes.
Could the air leak be caused by something else in the system like one of the double check valves. I couldn't really hear any air rushing through them like I could the bottom air line.
Can the pedal valve be rebuilt?

 

[5tonman1971]

Do you loose air while the truck is running?

My buddys 819 and my 923a2 you can hear the air system bleeding down when the truck is shut off. I think this is a normal thing.

As as long as it's not leaking while the truck is running I think your in good shape.

 

[Floridianson]

Looks like most Treadle valves can be serviced. I'm a big fan of air tool oil to see if that helps with sticking stuff so you might start there.

 

[PureMayhem]

Do you loose air while the truck is running?

My buddys 819 and my 923a2 you can hear the air system bleeding down when the truck is shut off. I think this is a normal thing.

As as long as it's not leaking while the truck is running I think your in good shape.

It is leaking all the time but I just can't hear it when engine is running. The compressor kicks in every few minutes while the engine is running. The pressure stays between 105 and 120 which I think is about normal.

 

[PureMayhem]

Looks like most Treadle valves can be serviced. I'm a big fan of air tool oil to see if that helps with sticking stuff so you might start there.

I will give that a try and report back.

 

[PureMayhem]

Ok I finally got around to replacing the treadle valve that has solved the problem. I no longer hear any air leaking into the intake stack when I turn the truck off. Thanks to Castle Bravo for his used treadle valve.

 

[Floridianson]

Do you loose air while the truck is running?

My buddys 819 and my 923a2 you can hear the air system bleeding down when the truck is shut off. I think this is a normal thing.

As as long as it's not leaking while the truck is running I think your in good shape.

Not normal the M931 I got from Pete would hold air for hours.
Glad to see you got her right Mark of the Mayhem

 

[162tcat]

Does anyone know if there is a rebuild kit available for the treadle valve? One of mine is leaking too and needs to be rebuilt or replaced.

 

[PureMayhem]

Try EriksMilitarySurplus.com . They have a rebuild kit. I will probably pick one up for my truck just in case mine starts to leak again.

 

[162tcat]

Thanks for the info! Order placed.

 

[plode]

Is there an exploded parts diagram of the treadle valve? That would help in rebuilding it...looks like quite a few o-rings and springs

 

[PureMayhem]

Is there an exploded parts diagram of the treadle valve? That would help in rebuilding it...looks like quite a few o-rings and springs

I downloaded this from the Bendix site . PN 102352

 

[PureMayhem]

Ok I finally got around to replacing the treadle valve that has solved the problem. I no longer hear any air leaking into the intake stack when I turn the truck off. Thanks to Castle Bravo for his used treadle valve.