M931A2 Brakes

[captnron]

So you need to remove the check valve and complete the circuit to the rear relay valve. It the brakes work fine then ite that double check valve. If you have already replaced that valve let me know

Yes I already replaced it with a Haldex KN25060. Could it be I need to reverse the check valve

 

[captnron]

You have a few double check valves. # 6 is located drivers side frame rail right about where the transmission and engine bolt together.

Have you replaced it?

This is the first check valve that air goes thru from the brake pedal on its way to the rear brake relay.

You may also remove the vent line off of the treadle valve. It is the lowest line on the firewall. Just to check that something hasn't clogged that line

Yes, I replaced that check valve and the one just aft of that one, on the frame also .

 

[simp5782]

Ok. You have replaced all the check valves.

Do you hear the brake exhaust from the rear of the truck when you let off the brakes?

 

[captnron]

Ok. You have replaced all the check valves.

Do you hear the brake exhaust from the rear of the truck when you let off the brakes?

No I don’t

 

[simp5782]

No I don’t

Is your abs light on? If no. Pull the fuse from behind the light and unplug the ABS sensor plug from the rear relay valve. And try your brakes

There are solenoids that hold and release air pressure in those relay valves. If you have air coming to those relay valves and its not constant from the pressure then the next place is the relay valves. So with it not making any exhaust release. Something isn't letting it vent

If you do not have the p2p program download it in the 5 ton tm section


Everything in green is activated during the brakes being applied.

Inversion valves and quick release valves in the step work with the spring brakes not service

 

[captnron]

Is your abs light on? If no. Pull the fuse from behind the light and unplug the ABS sensor plug from the rear relay valve. And try your brakes

There are solenoids that hold and release air pressure in those relay valves. If you have air coming to those relay valves and its not constant from the pressure then the next place is the relay valves. So with it not making any exhaust release. Something isn't letting it vent

If you do not have the p2p program download it in the 5 ton tm section


Everything in green is activated during the brakes being applied.

Inversion valves and quick release valves in the step work with the spring brakes not service

Ok thank you for all the information. I will do some more troubleshooting. I will let you know what I find.

 

[simp5782]

Ok thank you for all the information. I will do some more troubleshooting. I will let you know what I find.

My number is in my signature below. Shoot me a text tomorrow and walk you through it.

 

[m715mike]

If I may interject here....


Wes, the time and effort you put into helping people on this forum (myself included) is outstanding! Your efforts do not go unnoticed and are greatly appreciated. Thank you, Sir!


Ok, back to break troubleshooting.....
I’m looking forward to seeing how this problem is resolved.

 

[captnron]

Wes, thank you for your efforts and time helping me understand this dam air brake systems. I greatly appreciated all your knowledge. I did not look at the vent on the front passengers side glad had, it was plugged up. 98G in the beginning had mentioned it. Thank you! That fixed the problem . I learned a lot from this.