air pressure problem M931

[M931]

i have problem built up air pressure, no air, but when i close the valve on side on tank just after the airdryer it built up air on secondary, when i open valve i can hear air leak from the airfilter pipe

 

[fasttruck]

Governor stuck ? Ejector Valve on air dryer stuck open? Valves at rear of chassis for pintle trailer connections open ? Drain valve open someplace ? Any info in -20 annual about this ? Just thinking.

 

[M931]

all the valves for trailer are closed, all valves front and rear are closed, there are air from air dryer to the tank, from tank output on the side there is a handle valve when that is closed it build up pressure, all drain valve is closed.

 

[porkysplace]

Sounds like it could be a issue with the power protection valve .

 

[M931]

do you know where that is fitted… thanks

 

[sandcobra164]

The first tank you are closing off is the wet tank. Each successive tank has a check valve as well which will help you to identify what is leaking. Start by opening the wet tank valve that you closed to build air. Trace the line to the next tank up and repeat your test. If successful, open that tank and move on to tank 3. If that works, same for tank 4. Report back how far up the line you get and we'll dig into individual systems. Pressure protection valve symptoms would be different than what you are reporting so far so we'll look elsewhere for now. (I can detail later but for now let's work this angle).

 

[porkysplace]

do you know where that is fitted… thanks

On the air tank.

[h=1]Air Brake system troubleshooting[/h]

 

[M931]

thanks for help, i report back

 

[M931]

when this valve is closed on air tank i start it and it make airpress to max, except this tank, when i open valve i can hear air blow out..

 

[simp5782]

You are looking for a leak on the secondary air system side. Close the primary system valve on the front of that same tank. Use a shop air compressor and charge the system using it so that the truck is not running so you can find the air leak