Just did one of the two wheels I have off my M923A2 that is leaking in the exact same way yesterday. As others have said - you need to break the wheel down, separate the halves and replace the o-ring that seals the two halves up.
It's a two-man job and about two or three hours - at least for my first time. I think we could do this again in much less time now that we have done one. I bought the o-ring's from Erik's Surplus and he shipped fast.
Basic steps (front tire):
Order parts.
Ensure you have tools/sockets that fit the wheel lug nuts and wheel half nuts. You will need a schraeder valve tool in order to remove/install valve stems. Order any missing tools like a really big torque wrench that goes to at least 425 lb-ft.
Chock truck wheels.
Jack up the wheel to be serviced. Place jack stand on firm surface and support axle. If need be, put block under jack - especially if working on soft surfaces. You may need to loosen the budd nuts first - before jacking if you don't have a big a** impact gun or Robotool that can do the job without using the weight of the truck against the ground to keep the wheel from moving.
Remove CTIS shield - four nuts - two large (1-1/8"?) doubled nuts and washers, two hub bolts and washers.
Watch out for the shield spacer behind the shield - note that one spacer is shorter than the other to account for the CTIS manifold fitting.
Take a picture with the cover off for reference of CTIS hoses, manifold, turret valve stem, and so on for later reference.
Remove valve cap and schraeder valve stem from CTIS manifold to deflate tire.
Use 9/16" wrench to remove fitting from CTIS tank valve hose that feeds the tire turret valve stem.
Remove hub bolt holding CTIS manifold assembly - wiggle it off as there is an o-ring underneath that covers the manifold tube that provides air through the hub.
Check o-ring for cracks/wear or deformation. Replace if needed.
At this point you should have a basic wheel (deflated when the manifold valve stem hose was removed on the hub.
DO NOT work on a two-piece wheel that retains any air pressure. The valve stem (if you don't have CTIS) should be removed to ensure no residual pressure remains. Disassembly of a two-piece wheel with internal pressure can result in BAD THINGS (tm) happening to people and objects nearby.
Checking for LH threads (left side) or RH threads (right side) and using air impact or BFW remove the budd nuts from the hub - have Soldier 2 stabilize wheel when the last nut comes off.
I used a cargo dolly to get under the tire and lift tire/wheel off hub. Move to an area with room to work and swing a really big wrench - if wheel starts to fall over - stabilize it quick or get out of the way!
Draw a arrow pointing at the turret valve stem / centering hole through the two wheel halves on the tire.
Remove the nut holding the counter-weight and the weight from the wheel - note the orientation to the 5:30 position relative to the turret valve stem.
I used penetrating oil on all the wheel studs and nut the night before so they weren't taken off dry - if you haven't prelubricated things - do so now.
Using impact tools remove wheel nuts - loosen each nut a little at a time as you go around so as to not distort the outer two-piece wheel half.
Using pry bars, gently pry around the perimeter of the wheel half to lift outer wheel half from tire. Some penetrating oil between the wheel half and the tire into the bead between tire and wheel speeds the process of unsticking the tire bead from the outer wheel half.
When separated, reach down inside remaining wheel half and fish or hook out the o-ring with a probe of some kind. My inner wheel half was a bit grubby/rusty in one location but otherwise looked good! Your options at this point are two-fold: a) continue to disassemble wheel to remove the inner wheel half from the beadlock/tire for further cleaning and painting (if it's nasty/rusty and unlikely to seal well, or b) clean-up what you can of the o-ring seating area with the inner wheel and beadlock still in place, replace the o-ring and try your luck.
My wheel was clean inside except for the one area where it looked like water had pooled and built up crap that caused the rubber to abrade and fail. I chose option b). Some effort with a pick and screwdriver and other little tools to get in their and scrape and clean it out in order to provide a smooth environment for the seal to live. I also checked the outer wheel half and found a couple notches in the seal surface - maybe a dent/edge and some hardened and pooled paint leading to ridges. I cleaned them up with a file and a bit of paint on all bare metal to prevent future rust.
When the surfaces are clean and free of debris and if need be painted, lube the new o-ring liberally with grease and tuck it down into the grove at the bottom of the inner wheel half. I also lightly lubed the bead that would press against it on the outer wheel half. You could try and re-use your old o-ring. Mine was a 2010 rebuild and the o-ring was deformed and squished as compared to new. I wouldn't want to take the chance for a $12 item...
Checking the centering hole orientation, lower the outer wheel half onto the inner wheel studs ensuring valve stem is sticking through the centering hole.
Gently press the outer half down to seat the o-ring evenly.
Put your flanged wheel half nuts on by hand and run them down until just short of contacting the outer wheel half.
Tighten in a criss-cross pattern to seat the outer half - tightening each nut just a little bit at a time - you don't want to bend the wheel or distort the o-ring by tightening one nut too much.
When all the nuts are seated and the wheel halves have drawn together, get your big torque wrench out and in a criss-cross pattern, tighten each wheel half nut to 210-240 lb-ft (TM 9-2320-272-24-1 - page 2-36). When done, go around and check each wheel-half nut for proper torque again.
I installed a schraeder valve in the turret valve stem. Using a clip-on hose, I filled the tire in stages to 70 psi - checking for leaks along the way. Soapy water at the wheel half junction can help locate if you still have a leak. If you do - start over with disassembly after deflating tire. You can check the turret valve for leaks too - that has a gasket or o-ring and can be a source of leaks.
Put the counter weight on in it's proper place (5:30 tot he turret valve stem) and tighten the flanged nut holding it in place.
With Soldier 2, maneuver wheel back into place. Checking wheel orientation against the manifold pipe on the hub using your previous reference picture(s). Maneuver wheel/tire onto hub and while pushing the tire bottom in, hand-thread one budd nut onto a bottom stud. Hand-thread remaining nuts on to start. Run the nuts down to center-up the wheel on the studs.
Remove jack-stand and lower truck until wheel is lightly on the ground.
Tighten budd nuts to spec with your big torque wrench - 400-425 lb-ft (TM9-2320-272-24-1 - Page 2-80).
Lower wheel the rest of the way and remove jack.
Check o-ring on the manifold air line on the hub first for damage, you can lubricate it lightly with silicone grease, install CTIS tank valve assembly and secure with one hub bolt.
Remove the schraeder valve previously installed in the valve stem.
Screw CTIS line adapter down over the turret valve stem. Check for leaks. There are apparently o-rings inside the hose to turret valve stem adapters which may need replacement if damaged.
Install spacer into inside of CTIS shield - ensuring short leg on spacer will sit on the CTIS manifold's valve flange. Put the hub bolts through to hold everything together and install on wheel. Hand thread hub bolts into place - ensuring the two CTIS shield tabs are placed over the two respective wheel half studs. Add washers to the wheel stud, hand thread nuts and tighten all four to 60-100 lb-ft (TM 9-2320-272-24-2 - Page 3-640).
You're done. Enjoy a cold drink of your choice and admire a tire that will not be flat a few hours later. mine is still holding air nicely after two days. I'll be doing a rear tire this weekend.
A safety recommendation - if you had a front tire that had a leak and regularly would be flat I would rotate that tire to one of the rear positions. It's possible the tire may have suffered internal damage from the truck's weight sitting on it. A front tire is NOT the tire you want to blow out when driving the truck - improve your odds and move that tire to a rear location.
Cheers,
Clarke
Editied to add/correct torque specs and improve readability.
