Haulnpoop

[James L]

I have a 2006 Mack vision yesterday it ran all do with absolutely no issues today I won’t build an ounce of air any ideas 

[67RModel]

I guess it could be two things:

1. Compressor governor is not cutting in. The compressor is gear driven so its turning so long as the engine is running but in this case not actually compressing air. 

2. There is a catastrophic failure of the compressor discharge line causing zero air to enter the air tanks.

I guess I would inspect the discharge line from the compressor all the way to the wet tank with the engine running and see if I could find a leak. If no leaks are found then go after the compressor governor...

Edited May 13, 2022 by 67RModel
typo

[63BMack]

Bypass the air dryer to see if it builds air. I have had 2 of them plug up, I put a fitting in between the inlet and outlet to get by until I can get a cartridge. 

[Joey Mack]

I have a #10 JIC male fitting that hooks to my shop air, i take the discharge line off the compressor, and hook shop air to it. my shop air pressure is higher than the gov. cut out on the truck. with that , i can fill the truck and it will purge air normally if the system is good..  this way you dont need a noisy engine running while you look for leaks..  if the truck system is good,,,  check the compressor, and in some cases the drive gear will slip, on the aux shaft.  with the line off, you can crank the truck and see if air is coming out,  it will be hard to tell if it is the correct pressure, without making a line to hook to it then hook to the (empty) shop compressor, any portable compressor will do. to see if it builds air in the shop compressor..  This may seem like a bit of work to do some tests, but.... it works...  jojo