Air Leak

Don't forget to spray the soapy stuff on top of the main airbags. If you still have 30 and 60 in the morning, you won't be able to hear the leak. It will be a little pissy bubble in the soap solution.

 

No audible leek under the steering wheel? Probably the "money maker" the other post talked about. Some(most newer trucks) use a quick disconnect to the brake switch. Old ones screwed on. Its not unheard of for these to quick disconnect fully or leak off slowly(especially if you have recently hit the brakes hard.Remove screws,trim and pull up floor liner to check.

 

It's probably the valve I mentioned then. If you are mechanically inclined, you could isolate that line and find out yourself. If not, mention what you've already done to a Cummins mechanic and tell him my suggestion. That valve is around 700 dollars.

 

It could also be leaking off at the back of the air governor. If so, youd have to replace the governor, which the last one I bought was 28.00, but it was for a cat.

 

My leak, albeit on a Volvo, was the air line connection to the trans.

First time in the shop they clipped the hose and reinserted into the quick connect fitting. It worked for a week.

Then leaked again, loud enough to hear over the engine idling. Second repair replaced the fitting and has been good since.

Mikeeee

 

I just turned my truck into the shop. 7 psi per minute leak. I wouldn't worry about an air leak that passes a pre trip on a company truck.

 

I had a cracked glad hand hose. It was barely audible and passed the pretrip. I scaled and parked, went inside for my scale ticket and then went back to the truck.

I checked it again and it was cracked even more. Enough that it failed the rest spectacularly...


Mikeeee

 

Yeah, they do get worse fast sometimes.