Air dryer service

[King]

M35A3 air dryer dated 2008, so I thought I would do the TM service. I was able to pull the dryer but the filter is stuck, so after using a ratcheting strap to stabilize the unit I decided to go ahead and skip to the pressure valve replacement. If it wasn't for bad luck, I don't think I would have any luck! Please see the pictures, do I just buy a new dryer! Filter is still stuck, pressure valve busted off, yep just bad luck. PB Blaster on filter threads.

 

[rustystud]

I would buy a Bendix "AD-9" dryer and install it. The parts are 1/3 the cost of the military unit and available everywhere.

 

[Scar59]

Yep, I had to cut the filter off my dryer w/ a high speed cut-off wheel. Had I not already had a service kit for it, it would have been chucked in the trash and replaced it w/ a commercial replacement. That filter is corroded to the a housing.

 

[King]

Does the bendix fit with the original mount, what about the fittings? Any issues I should be aware of before I order one? Thank you��

 

[Scar59]

I would take your existing unit to a OTR truck parts house, they can compare and adapt any fitting issue. I use Total Truck Parts here in Lou. KY. The guys are very helpful.

 

[gimpyrobb]

Will(pawnking?) has some new ones that fit and are cheap. Might send him a PM and see if he still has some. ZiggyO had some too if Will is out.

 

[ZiggyO]

I have some....$95ea plus shipping...........

Z

 

[rustystud]

Does the bendix fit with the original mount, what about the fittings? Any issues I should be aware of before I order one? Thank you��

You probably will have to drill some different holes to mount it but it should fit in the space of the old one. The fittings will not be hard to change out either.

 

[King]

I was able to extract and replace! After a substantial amount of screaming and a little cursing, sorry neighbors! I hope to have it all cleaned up and installed tonight. I never did figure out what the white powder coating under the paint was, does anyone have any idea? Looks like some form of corrosion or corrosion protection, barley visible in the last picture. The paint flaked off and the white stuff under the paint is coming off.

 

[Scar59]

The white stuff is early signs of exfoliation (corrosion) from the aluminum housing breaking down.

 

[brianp454]

Early signs? It looks to me like it is falling apart. Did I miss something? FYI I recently picked up an AD-9 per Rusty advice from a wrecking yard for $20. I'm investigating the best place to mount it as I have time.

The white stuff is early signs of exfoliation (corrosion) from the aluminum housing breaking down.

 

[Jeffval]

I've got a M35a3. It only has 6000 miles on it and has been sitting in a garage since 1993. After shutting off the engine, i released the air from the air tanks. I noticed about 1 cup of water coming out of my right side air tank after I released the valve. The other 2 tanks just had a fine mist. Somebody told me to check the air dryer. Ive fixed just about everything on this truck and I got to the air dryer filter today. I reached up underneath the truck and unscrewed the filter. It was pretty heavy in my hand. I'm assuming it's contaminated? Then I tried to remove the internal filter coalesing part and the top of it easily and surprisingly broke off in my hands. I did not unscrew and drop the dryer. I just immediately pulled out my phone and ordered the rebuild kit and filter replacement. Any tips or suggestions on how to remove the filter coalescing part? Does it just pull straight out or unscrew? Do I need to disassemble the air dryer and clean the inside? Also, I saw Rusty suggest ordering the Bendix "AD-9" dryer but when I looked it up, it's only 12 volts. My current dryer is 24 volts, so how would a 12 volt Bendix "AD-9" dryer be compatible with my truck? Also, I saw no visible signs of corrosion or oxidation on the outside of the dryer, which I'm assuming it's okay. I dont even know if the heater works. Im assuming it does but i was getting eaten alive by mosquitoes and had to go inside the house. Lol. Do the heaters normally go bad along with a bad filter?Is my current dryer worth rebuilding or should I cancel the order and get the "AD 9"? I hope to be driving this truck in 3 days. Thanks Jeffval

 

[Mullaney]

I've got a M35a3. It only has 6000 miles on it and has been sitting in a garage since 1993. After shutting off the engine, i released the air from the air tanks. I noticed about 1 cup of water coming out of my right side air tank after I released the valve. The other 2 tanks just had a fine mist. Somebody told me to check the air dryer. Ive fixed just about everything on this truck and I got to the air dryer filter today. I reached up underneath the truck and unscrewed the filter. It was pretty heavy in my hand. I'm assuming it's contaminated? Then I tried to remove the internal filter coalesing part and the top of it easily and surprisingly broke off in my hands. I did not unscrew and drop the dryer. I just immediately pulled out my phone and ordered the rebuild kit and filter replacement. Any tips or suggestions on how to remove the filter coalescing part? Does it just pull straight out or unscrew? Do I need to disassemble the air dryer and clean the inside? Also, I saw Rusty suggest ordering the Bendix "AD-9" dryer but when I looked it up, it's only 12 volts. My current dryer is 24 volts, so how would a 12 volt Bendix "AD-9" dryer be compatible with my truck? Also, I saw no visible signs of corrosion or oxidation on the outside of the dryer, which I'm assuming it's okay. I dont even know if the heater works. Im assuming it does but i was getting eaten alive by mosquitoes and had to go inside the house. Lol. Do the heaters normally go bad along with a bad filter?Is my current dryer worth rebuilding or should I cancel the order and get the "AD 9"? I hope to be driving this truck in 3 days. Thanks Jeffval

.
How about a local NAPA store and possibly a Haldex brand dryer?
Not positive, but this should be a good part number @ NAPA: MBI DA33110X or N50011K
.

 

[rustystud]

I've got a M35a3. It only has 6000 miles on it and has been sitting in a garage since 1993. After shutting off the engine, i released the air from the air tanks. I noticed about 1 cup of water coming out of my right side air tank after I released the valve. The other 2 tanks just had a fine mist. Somebody told me to check the air dryer. Ive fixed just about everything on this truck and I got to the air dryer filter today. I reached up underneath the truck and unscrewed the filter. It was pretty heavy in my hand. I'm assuming it's contaminated? Then I tried to remove the internal filter coalesing part and the top of it easily and surprisingly broke off in my hands. I did not unscrew and drop the dryer. I just immediately pulled out my phone and ordered the rebuild kit and filter replacement. Any tips or suggestions on how to remove the filter coalescing part? Does it just pull straight out or unscrew? Do I need to disassemble the air dryer and clean the inside? Also, I saw Rusty suggest ordering the Bendix "AD-9" dryer but when I looked it up, it's only 12 volts. My current dryer is 24 volts, so how would a 12 volt Bendix "AD-9" dryer be compatible with my truck? Also, I saw no visible signs of corrosion or oxidation on the outside of the dryer, which I'm assuming it's okay. I dont even know if the heater works. Im assuming it does but i was getting eaten alive by mosquitoes and had to go inside the house. Lol. Do the heaters normally go bad along with a bad filter?Is my current dryer worth rebuilding or should I cancel the order and get the "AD 9"? I hope to be driving this truck in 3 days. Thanks Jeffval

They make a 24 volt model. You can also order the 24 volt heater kit separately

 

[Jeffval]

.
How about a local NAPA store and possibly a Haldex brand dryer?
Not positive, but this should be a good part number @ NAPA: MBI DA33110X or N50011K
.

I ordered the rebuild kit and filter. This truck should be fully operational by

They make a 24 volt model. You can also order the 24 volt heater kit separately

I ordered the filters and rebuild kit for the air dryer. In the meantime I've been starting the truck and draining the air tanks. I don't understand why water keeps coming out of the right side air tank, especially since i live in the high desert in Montana at 5700 foot elevation and its such a dry climate right now? I detached the main air line leading from the compressor but just air pumps out and no water. Also, when excess air pressure is relieved from the tires, water mist sprays out from the valves. I have fixed everything on this truck except for excess water in the right tank and the heater temperature pull handle that connects to the open and close valve under the hood. I can't pull the handle out, so I go under the hood and push the valve open with my finger, relatively easy. Then I go inside the cab and I can only push the handle to the off position. There doesn't seem to be anything wrong with the handle, the cable or the valve. I can push the heater temperature handle in, but I can't pull it open to increase the temperature.

 

[rustystud]

I ordered the rebuild kit and filter. This truck should be fully operational by
I ordered the filters and rebuild kit for the air dryer. In the meantime I've been starting the truck and draining the air tanks. I don't understand why water keeps coming out of the right side air tank, especially since i live in the high desert in Montana at 5700 foot elevation and its such a dry climate right now? I detached the main air line leading from the compressor but just air pumps out and no water. Also, when excess air pressure is relieved from the tires, water mist sprays out from the valves. I have fixed everything on this truck except for excess water in the right tank and the heater temperature pull handle that connects to the open and close valve under the hood. I can't pull the handle out, so I go under the hood and push the valve open with my finger, relatively easy. Then I go inside the cab and I can only push the handle to the off position. There doesn't seem to be anything wrong with the handle, the cable or the valve. I can push the heater temperature handle in, but I can't pull it open to increase the temperature.

Disconnect the cable and spray some teflon fluid (your choice of brand) in it. Then work the cable back and forth. Sometimes you can get a small piece of debris in the cable and it acts like a oneway lock.
As far as the water goes. Remember you get a wild temperature swing from day to night in the high desert regions. That cause's condensation.

 

[silverstate55]

Plus heat & pressure together usually result in condensation. Make sure that the air compressor output hose goes to your wet tank first, then off to your air dryer…..could be that your air dryer is so in need of rebuilding that excess moisture is carried in the air storage system. I’ve gotten moisture sprays from tires before, usually when my compressor is overworked and causing more condensation than usual; without an air dryer or desiccant pack between the compressed air source and the air hose outlet, there’s nothing to prevent the atomized moisture mist from going into your tires. It also causes much of the rust on the interior wheel surface between the beads.

You’re on the right track….once that air dryer is fully serviced and tanks drained fully, you’ll notice the condensation start to drop off over time. Until air dryer needs servicing again.

 

[Jeffval]

Disconnect the cable and spray some teflon fluid (your choice of brand) in it. Then work the cable back and forth. Sometimes you can get a small piece of debris in the cable and it acts like a oneway lock.
As far as the water goes. Remember you get a wild temperature swing from day to night in the high desert regions. That cause's condensation.

Okay. Thank you, I'll try the Teflon. Where does the CTIS system draw its air from? I thought it may draw air from the air filter intake near the muffler, so I've been wrapping the air filter intake/ compartment with a plastic garbage bag when the vehicle is not in use.

Thanks, Jeffval

 

[rustystud]

Okay. Thank you, I'll try the Teflon. Where does the CTIS system draw its air from? I thought it may draw air from the air filter intake near the muffler, so I've been wrapping the air filter intake/ compartment with a plastic garbage bag when the vehicle is not in use.

Thanks, Jeffval

I'm sure you mean "where does the air compressor draw it's air from" correct ?
If you look at the air compressor you will see an approximant 2" X 3" square metal housing near the top of the compressor head. That is the filter intake. There should be a course fiber material inside the housing. That is the filter. Some trucks still have a hose attached to this housing that runs to the engine air filter.
Wrapping the filter with a garbage bag won't do much to prevent moisture from getting in. The best thing to do is attack the moisture in your air system. That means fixing the air dryer or installing an air dryer and draining your air tanks on a daily basis.

 

[Jeffval]

I'm sure you mean "where does the air compressor draw it's air from" correct ?
If you look at the air compressor you will see an approximant 2" X 3" square metal housing near the top of the compressor head. That is the filter intake. There should be a course fiber material inside the housing. That is the filter. Some trucks still have a hose attached to this housing that runs to the engine air filter.
Wrapping the filter with a garbage bag won't do much to prevent moisture from getting in. The best thing to do is attack the moisture in your air system. That means fixing the air dryer or installing an air dryer and draining your air tanks on a daily basis.

Hi Rustystud:
Air dryer is fixed with rebuild kit. Working great. Lots of water has been reduced to a very fine mist. The truck is fully operational now. Just one mire question about the crank case breather. There's an elbow, facing the front of the truck, which is a air line fitting. The elbow has no hose attached to it. I've looked all over the truck where a hose connected to that elbow would go? Thanks so much. Jeffval