MRAP tire and wheel with inner tube

[metalworker393]

Hello and how is everyone today. Okay so the weather isn't going to be too bad this week time to get wrenching on my deuce again. First thing im going after is a problematic tire/wheel.
I had posted about this previously , one of my tires keeps gong flat. Im going to try inflating it to 80 psi and see if I can find the leak. should I wind up wanting to go to the adding an inner tube, what size would be good? from what I have read, people are using the 1300/1400 tube size.
What would be a good tire stem to use ? should I put a flap inside the tire?
Does anyone have pictures of what they did ? I am using the steel MRAP wheel and the 395 Goodyear MVT tire. Any tips would be appreciated. Thanks ,and good weekend to all, metalworker393

 

[Clay James]

That could work on a steel MRAP wheel if you can get the valve stem to fit the large bore opening. Finding and repairing the leak is the best way because with a tube if it goes flat for any reason you're pulling it apart and repairing the tube. I've done thousands of tires and if it's tubeless I always try to keep it that way.

 

[rustystud]

That could work on a steel MRAP wheel if you can get the valve stem to fit the large bore opening. Finding and repairing the leak is the best way because with a tube if it goes flat for any reason you're pulling it apart and repairing the tube. I've done thousands of tires and if it's tubeless I always try to keep it that way.

Agreed ! If you ever experience a flat out on the road, a simple truck tire repair kit will work with a "tubeless" tire ( though a drill will help a lot ! ) . No need to even take off the tire. Busting down a tire on the side of the road is not fun or safe ! Even replacing a tire that big is a pain in the butt on the side of the road.

 

[bonedoc]

I'm in the process of removing my 395 MVTs and replacing them with new XZLs. Mine are mounted on A3 rims on the truck but the new XZLs came off of a mix of FMTV wheels and MRAP wheels. I agree with Ruststud. Leave it tubeless and find the issue. Unless you have a hole in your tire it can only be 2 places, the valve stem/gasket or the O-ring. I'd disassemble it and replace both. Then reassemble it and make sure you really torque the wheel clamp bolts tight. I had the first 2 I swapped leak slowly and I drained the air and retorqued the clamp bolts, that fixed it. Also, do you have a beadlock inside? They say you don't NEED one but if not you want to add it. That really helps to ensure the bead is tight.

 

[metalworker393]

Yep , I have the metal beadlocks in the tires, the wheels came with valve stems and the rubber grommets appeared to be in satisfactory condition. I have replaced the orange o ring twice on this peticular wheel. I also have a 3/4" torque wrench and torque the wheels (together) to 450 ft. lbs. I use a 5 point star pattern then rotate to the other 5 bolts. I torque them all first at 150, then 350, and final at 450.
getting a bit frustrated with this wheel. I cleaned the groove , and used BTR o ring lubricant to lube the oring and keep it from sticking . The other wheels seem to be holding air fine, just this one is giving me a devil of a time.
Thanks, metalworker393

 

[bonedoc]

I understand your frustration. Did you double check the valve in the valve stem? Make sure it is tight and seated correctly? How about filling it with air and dropping into a kiddie pool full of water? See if you see anything coming off it.

 

[Special T]

First off I believe the wheels are stamped tubeless only. You will rip the stem in a tube because they are not in the correct place.
Second I wouldn't crank down the o ring down that hard for the first tightening. I would find them all down hand tight then only go lightly say 50lbs or less till they are all snug then tighten down to spec.

The best way I have found to find an illusive leak is to put the tire and wheel in a warm shop laying flat and coat with a layer of diluted soap and warm water and let it set for 30 min if a leak is not readily apparent. Extra o rings and valve grommets should be in everyone's tool box. They are relatively cheap and can be hard to find when you need them. There are some standard commercial valves that fit the stem hole properly if you are not using the central inflation system. This change is convient because every tire shop has the air water valve and grommets in stock, or should if they do any farm/ag service.

 

[winfred]

whats the opinion of o-ring styles? of my 6 mraps 5 had triangular and one had a round sealing ring

Extra o rings and valve grommets should be in everyone's tool box.

 

[Special T]

Often times o rings deform under compression for long periods of time. I'm unsure of the diameter options for the military wheels but for heavy equipment in 25" there are 2 different o ring diameters. Using the wrong one usually makes it leak. In heavy equipment the o rings often look t shaped after sitting for long periods.

 

[Special T]

Improper torque procedures will often cause misshapen orings or if there is not enough lubricant or surfaces are not clean.

 

[metalworker393]

Thanks T, when I picked the tire and wheels up I took them apart and the old o rings were in there. I was able to get a number off of them and order replacements. I did clean the groove where the o ring sits to make sure there was no dirt or debris to cause a leak.
I will say however, these o rings are a lot thicker than the o rings I used in the A3 wheels I had on my other truck.

 

[Special T]

I would also add that lubing up the o ring helps it settle better while tightening down the 2 halves.