rapid air pressure loss - engine off - 07 Volvo 780

I would start looking at the air level system on the back axel, Volvo has an up dated part for the system. four air lines down to two. After volvo replace the leveling system on my truck ( 110 .00 for the part plus labor ) 90% of my air leaks were gone.

 

I had the same problem. It turned out to be a air valve located on the frame above the batteries

 

If your loosing that much air that quick just walk around the truck listening, the leveling valve you can push down on the arm after the bags fill to stop it from leaking in sometimes. While were talking about air leaks and I hate to hijack your thread but I have a valve leaking behind my engine oil filters on my d12, what would that be?

 

Mine is being fixed tomorrow. Granted it's 2005 but the company I'm leasing on with won't pass it until there are no air leaks. My leak is the air leveling valve on the front airbag, on the front drive axle...driver's side. BTW, they found it with a spray bottle and soap/water mixture...make sure the spray bottle is of the industrial type that will shoot about 5 feet or so.

 

I'm tackling these issues today.

what i'm curioius about is what i've heard refer to as the wet tank and dry tanks. Does that apply to the volvo780?

what I know for sure: the front air tank(towards the steer tire) has a hairline crack. This has been the case for over a year. I've been told that it's the accumualtor tank. The two other tankshave no known leaks.

The new problem just started this week. i'm losing all my air in about 3-5minutes.
When the truck is running, it builds to 120-130, then all is ok(though i think the air pressure overfill release is cycling more frequently) every 90 seconds when rolling down the hiway bobtail.

the way i'm led to believe how the system works is this- the accumulator tanks fills first, then fills the other two tanks, with no way for the two tanks to drain into the accumulator.( that's why I don't think the accumulator tank is the issue) it's a $550 tank to replace(not including labor)

when i turn off the truck, it's the accumulator tank that's making the most noise, so it's hard to identify other leak noises.

Any input is appreciated.

 

the last time I got the same issue it was ISX turbo actuator. It is connected to front brake tank and when engine is on it dumps air.