Air suspension

[VirgilB]

I have a 2000 Chieftain, freightliner chassis. Three of the four air bags are inflating, but the fourth one is not. It is on the rear passenger side. Their is no air leakage and the arm is ok. Can someone explain this or instruct me what to check?

[imnprsd]

So both your primary and secondary air tanks read ~110 PSI?

This might be a good time to call 1-800-Freightliner to ask their technical support team... and if you have a sticking check valve somewhere.

How does that ride-height mechanism work? If it's stuck, can you bang on it toe free it lose?

Please keep us posted.

[reeman]

Like air brakes, bags can be affected by water in the tank(s). If there is a petcock(s?) to drain the system somewhere at the lowest point of the system try releasing all air and see if some water shoots out. If the compressor dryer is not working then that can cause water problems. If your system is watering up then you might be able to fix things by simply drying out the lines and tanks. Something truckers do if they know what can happen to air systems if not checked for water in the lines frequently.
I have lost air brakes in the past because of dryer problems during cold and damp weather on a Mack hauling 30 tonne of pit run simply because the tank watered up and froze the lines sticking the brakes off. Not a fun ride, but I did have a spare pair of shorts back in my locker so the lesson was not lost on me