M939A2 No Air Building

[71DeuceAK]

I'm sure this has been asked a million times over the 20 years of Steel Soldiers' existence by now, but I didn't find anything relevant with my search terms, or looking through the -10:

'91 M923A2: Roommate's truck. We went to get it running today for the first time since parked October 2019. Temps were in the teens, dug it out from a couple feet of snow, aka it's been dormant for almost half a year.

Got the truck running. Background: It's chilly and batteries were known to be somewhat self discharged by now so a kerosene space heater of the "Jet Engine" type was used. It warmed things up substantially before cranking was attempted at 16*F ambient outdoor temp on a frozen, dormant truck, i.e cold-soaked.

No air built...Primary and secondary registered nothing. Modulating engine speed to warm up the air compressor and thus blow warmer air to unstick anything frozen was attempted, albeit not very long as we weren't entirely sure what we were doing.

Air audibly dumps from the (primary, wet?) tank or rather the vicinity of such, i.e behind drivers side step, but not for long once vehicle engine shut down. Thinking something stuck open? Or something froze and broke over the winter?

It's at home in the driveway and still have 90-100 gallons of fuel for the house left (stops pulling at about 35) so not a total SOS...yet...but wanting to ideally fix this weekend.

Thanks!!

 

[simp5782]

Air diagnostics. Start at the basics. Remove the line at the air dryer coming from the drivers side frame rail. Truck running see if you have air. IF NO, then you need to remove the line from the compressor rear and see if there is air discharging.
if you have air from that line on the frame rail, a forceful amount of air. Hook it back to the air dryer. Then remove the hose that goes from the dryer to the wet tank and see if you have air. IF NO then you have a froze up air dryer. IF yes air is present then we will go from there.


Start with the basics first to see what is building air or not