Air dryer/governor/compressor issue...

Oil buildup in your cartridge, cold weather is exacerbating the lack of maintenance.

Change your cartridge immediatley, then throw some rubbing alcohol into the feed line of the compressor, so it can clean the oil out of the air lines.

Check the seals on the air compressor, 12.7 is gear driven, so youre getting oil blow buy from the gear train into the air system. Unloader valve is not the culprit. It's just letting engine oil pass through. The tiniest amount will clog up a filter dryer.

 

I wouldn’t put much faith into the gauges. Beat on them, see if they change. Did you drain all the tanks? I agree, take SS line off at compressor and put some alcohol into the SS line. You say gauges don’t move. Can you pump it down, till buzzer comes on @ 60 and buttons pop? If so, it’s probably OK. You can adjust the governor down a bit if desired. Instructions w/package, ( remove black plastic cap, turn clockwise w/screwdriver to lower, counter clockwise to raise cut out pressure. Hopefully you bought a new, not a reman governor. New Bendix is expensive. The New Aramak has done me well. The reman Aramak is cheap junk. Only lasted me a couple weeks. You can almost change the whole dryer, for the cost of a new filter. It’s almost easier to change the whole thing, than the filter. Besides the spitter valve usually fails. By the time you buy all that, it’s much cheaper just to swap the whole dryer out, every 3, maybe 4 years max. Thats within Bendix linehaul recommendation. I’ve pushed them 5 yrs twice. Both times I froze up, and found myself changing them, while laying on the frozen ground, live and learn. Catch them on sale @ Fleetpride or Freightliner. That’s been my experience anyway. Best to carry a spare govenor. I’ve had them crap out quite a few times. Cheap insurance. Good Luck. Be glad it’s an AD9. Newer style compressor/dryer is expensive and a PITA to change.

 

That explains why my brand new compressor pushed so much oil. Makes sense. Manufacturer claims it’s normal, and AD9 filter is large enough and can handle the oil. I’ll have to check it, now that My engine is rebuilt. That is after I fix the head gasket that blew @ 200k. It never ends, Lol

 

If it's popping off at the correct pressure, that means the governor is seeing that pressure from the tank, and sending the signal to the drier to pop off, while simultaneously sending that signal into the compressor to unload.

Yes, it can definitely build air with unloader issues.

I'd pull the governor off of the air compressor, but leave the hoses connected. Then use the threaded pipe orifice for the unloader signal on the compressor side of the governor, and tap in a pressure gauge to verify signal once pressure hits 120, or it pops off.

If you don't have a pressure gauge and we assume the dash gauges are correct, just unbolt the governor and start the truck. Make sure air comes out of the orifice going into the compressor when the drier pops.

You didn't plug your signal hole to the unloader when you installed the new one, right?

 

Ok, dryer mounted. So the air line is the unloader signal. Pull it off at the compressor and see if you get air there at 120-125.

Make sure there's no kinks in that line too