Bottom of air dryer leaking. In parking lot

I know I can search this, but please forgive the directpost. I still have some daylight so i'm asking for help immediately. Using my phone so not sure if phto will display. I'm in my M923 A1, the air dryer has constant air being released from the very bottom most part of the dryer. Any thing I can do to get this truck home so I can take my time to resolve properly and get out of this parking lot?

That's looks like the purge vale, they get stuff/junk stuck in there. Try looking up in it or spray some thing up there. Some times they will clear themselves when the air bleeds all the way off.

Stick ur finger in there and push it back up. Be brave it wont bite. Then replace your air dryer.

thank you I'll give it a try.

Will attempting to turn the bolt accessible through the bottom help/hurt anything?

Nope wont do anything the part comes out from inside. Spray wd40 in there push it back up. When you reach governed pressure and the governor tells the unloader to stop making pressure it also makes the air dryer purge moisture thru the expello valve. Which is what is stuck open on your truck. Its supposed to spring back up.

I have tools, but no wd-40 at the moment. I'll have wd-40 in about 15 minutes.

Were you able to get the valve pushed up and closed?

Not yet. Can I push the heck out of it. I tried without the wd-40 and it didn't budge. Have wd-40 now. About to try it.

Yup push up hard with the truck off

Mine did this too with the original air dryer. May need a punch/soft hammer to pop back up but mine went up with just a finger's push. Replaced it with a bendix AD-9 with 24v heater

That didn't stop the dryer leak. When I shut the engine down, I heard what sounded like a new leak under the engine cowling. It was this (photo). Coming through one of the holes, not the liNe connections.


I'll admit I'm no mechanic, but with help from the site i've been able to maintain it myself. Thanks for the help.

I'll try lighly tapping with a socket extension and hammer.

That didn't stop the leak.

I got it going. Still leaking, but barely. It's holding 120 psi. I should make it home. Guys, once again...thanks to all of y'all.

If it happens again, turn the truck off and dump all the air out of the system. Frequently this will allow it to resolve itself.

Looks like that new leak is from the exhaust port of the fan-stat valve. Again, mine started leaking out the exhaust port about 2 weeks ago and I've replaced that too.

frioman said:

I got it going. Still leaking, but barely. It's holding 120 psi. I should make it home. Guys, once again...thanks to all of y'all.

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Frioman,
Just catching up to your dilemma, looks like your big unit is in need of a little preventative maintenance, she's talking to ya. Glad you got her home. Need to carry tools and supplies when you're out and about.
JC

there are several folks in the classifieds selling new OE complete drier units very reasonable and mrap style replacements that will also work perfectly. They are much cheaper than trying to source all the parts for a complete rebuild not to mention labor time. Just a fyi, ask me how I know

I had the exact same problem with my m923a2. Had it sitting all winter outside and when I fired up the truck, it wasn't building pressure. I hadn't been able to use it for 2 months, but today decided to try something. There was air coming out of the same bottom orifice the OP mentioned, you could feel it and hear it. I took off the cover, it's held together by 3 screws. You could then see a snap washer, which I removed. That didn't do anything, but there was a nut visible in the center of the housing. I turned it with a wrench a couple times counterclockwise, but it was free wheeling. So I turned it clockwise for good measure. I then fired up the truck and to my glee there was no more leaking air. Pressure reached 120 PSI and I was on my way.
I don't know if this was a fluke or it will leak again in 5 miles. Any thoughts?
I tried to upload photos, but wasn't able to, sorry.