Air brake leak


New Recruit
2005 freightliner century and when I'm driving it constantly loses air from sitting still with the brakes out it just does not hold the air in there when I press the brakes in the primary side its fine when I press the secondary line in it just you know it it comes down but then it hisses bad and when I get the truck to run and build it up it's fine so I'm just trying to figure it out what's going on with my my truck

Abs/tractor values/tank valves/

And it's also feeding back into my dashboard I've got a brand new tractor valve putting a brand new quick release valve on here uh I just wanna know why is it feeding back

Air bags solid break chambers solid no leaks on test


Veteran Expediter
If it is feeding back into the valve on your dashboard, one of your brake chambers is bad.