Hi everyone. I am new to the forum. I have a 1986 max superliner and I’m scratching my head on this one. Air will not build unless I pump the system to nearly empty. To date, I installed a new air dryer, new governor and the uploader valve is clean as a whistle. All the lines appear to be clear.
The truck came back from having a new frame put under it. A few air lines were replaced. I found a loose fitting and tightened it. Right after that, the air dryer kept purging. I replaced the governor and the purging problem went away but now this new problem has appeared. The old air dryer had a stuck check valve and hadn’t been serviced in quite some time so I replaced it with a new one. I am still having the same problem with no air building unless the system is bled down to nearly nothing. I had to run the truck for the day so I “tricked” the compressor into staying on by loosening the line that goes from the air dryer to the governor. Any thoughts?