Impossible to find air leak

this doesnt sound like the issue you're having however, for the mention, my truck is in the shop, the tech called my description an "air tank purge".

the air system releases air upon start up of the motor after sitting for several hours (10hr brk) with the motor off on occasion. there is a leak sone where, the low air warning begins after about 6 hrs,

The shop is working on another problem with the regen system before the air system is addresed. will know more later.

 

My issue starts at the seat. The air in my seat leaks while I am going down the road. Checked for leaks but never found anything... The system will drain in about 2 hours to almost nothing. I found a leak at one of the rear brake line fittings but that only leaks when you step on the brake pedal, right? It's like the leak starts at the seat and drains everything else....grrrrr

 

You know I had a 2001 KW W900, had the same problem - It took some time but eventually it turned out to be the steel braid hose from the compressor mounted governor to the wet tank.
It was so old and worn that it was leaking all the way through the steel braid, you couldn't detect it with soap water or hear it, but it would hardly allow the pressure to build. Changed it and problem solved, it was like getting a new compressor.

 

When you say "wet tank" what are you referring to? I think I know but not 100% sure but are you talking about an added system that is used on some trucks for certain operation?

 

Wet tank is the first air tank off the compressor.

 

Been driving almost 10 years now and don't recall hearing that before, thanks 062 Now that I am a Big Rig owner, these are things I need to know, so I can fix them.

 

Air system explained
.air-brakes-how-they-work

 

Do you have pictures. I've been tring to find a air leak but haven't checked where you found your

 

Best thing to do is air the truck up by another source and get out the soap bottle. Could be a brake chamber leaking as well.