Tire flat!!

[Hoxman]

Hello,

I found my driver's side front tire (super single) flat the other day.
All the rest are ok and I did not start it up and let the CTIS bleed them lower because the idle rpms weren't high enough to put pressure in the system.

I aired it back up and it took 2 days to go down again. We sprayed the entire tire with leak detector (not an easy job on those big bastards.... And the ONLY leak we found was the valve core....

We pulled it out and it was corroded so I replaced it with off the shelf short valve cores from Auto parts store... Fit correctly (I think) and aired it back up... It went flat in less time with the new core in it......

Do they take special valve cores? Is there something else I'm missing? Anyone else had this? (I'm sure someone did)....

Any help will be appreciated!
Thanks!
-Hox

 

[Triple C]

Yeah, a search will bring up a ton of threads on this. I have the same problem on a 1400 super single. They tell me it is the o-ring. I took the tire and wheel off and replaced it with a spare but when the weather gets nice I might give replacing that o-ring a shot. There is a good thread about changing the o-ring with the tire still on the truck, I would do that if I hadn't already taken it off. Good luck.

 

[welldigger]

Probably either the o-ring between the wheel halves or the grommet around the valve stem where it goes into the wheel.

 

[Rambling Wreck]

My theory with the M35A3's is that the CTIS puts moisture inside the rims/tires, causing the o-ring and grommets to break down (or perhaps the metal and seal around them). I have disconnected my CTIS and when I did I had 3 tires that leaked pretty bad. I put the spare tire (never hooked to CTIS) in place of the worst tire and it has never lost a pound of air. That was over a year ago. Maybe the air dryers on these trucks just aren't as effective as they should be.

 

[welldigger]

Or they don't change the air dryer filter.

 

[Riktord]

RTV the o-ring...

 

[sandcobra164]

I'm just thinking out loud here but if the moisture has ruined the sealing surfaces, why not just install a tube. Sure, it will succumb to the same failure at some point down the road but it seems to me to be a simple solution to a common failure point. When the first tube fails, install another and you've bought yourself a few more years. I didn't research if there are good tubes for this tire size but alot of people run 395's on stock A2 rims so I'm sure there is a tube that would work for the A3 14.5 application.

 

[silverstate55]

Change the air dryer filter & use silicone grease (non-petroleum based) grease on the O-ring between the wheel halves and on the gasket/o-ring for the valve stem. That has cured the A3 wheel leak-downs I've helped with here.

 

[rosco]

I don't believe moisture has much to do with flat tires. Back in the days when tubes were common, and we used to submerge tubes, to find leaks, half the tires were then assembled wet. A we just had to fix the tire, and it happened to be raining, so things were wet. We didn't know any better - there were no tire shops.

You have a leak in one of the sealing surfaces, bead leak, CTIS leak, carcus leak, or wheel leak. Face it! Flat tires are a lot of work, so just get busy and look for it. There is no magic bullet. The best thing to do in self defense, is become a tire repair expert.

 

[quickfarms]

The valve stem seals can go bad and the filter in the air drier can get saturated. Do you drain your air tanks daily?

 

[Rambling Wreck]

I don't believe moisture has much to do with flat tires. Back in the days when tubes were common, and we used to submerge tubes, to find leaks, half the tires were then assembled wet. A we just had to fix the tire, and it happened to be raining, so things were wet. We didn't know any better - there were no tire shops.

You have a leak in one of the sealing surfaces, bead leak, CTIS leak, carcus leak, or wheel leak. Face it! Flat tires are a lot of work, so just get busy and look for it. There is no magic bullet. The best thing to do in self defense, is become a tire repair expert.

So, back in the day, you didn't experience leaking issues related to moisture, WITH tubed tires. That makes sense. I wouldn't expect leaks related to moisture in tubed tires. That isn't what this thread is about. It is about leaks in tubeless, split rim mounted tires. For this setup, moisture is a major factor in what causes leaks, particularly when the CTIS is present.

 

[trukhead]

Wehring suggested using Gemplers or other type of tire glop on the sealing surface of the split rim to prevent leaks. It is not the liquid lube but the paste stuff that prevents rim rusting and it also seals beads and should seal the oring area as well. It comes in buckets.

My bad little buckaroos, the stuff is Freylube:

"The original tire lubricant and rim rust retardant"

http://freylube.com/prema/:popcorn:

 

[glcaines]

Leaks in these tires is almost always the grommet under the valve stem, not the o-ring. The grommets are typically all dry-rotted that I've seen. Also, the brass nut on the valve stem is supposed to be torqued to 45 - 60 Lb-Ft. Mine were all finger tight when I broke the wheel down. The TM says not to put anything on either the grommet or o-ring. Every A3 wheel I've broken down and installed new O-rings and grommets in are 100% tight. The CTIS on my A3 works great. Also, if the air dryer is working properly there is never any moisture in the air tanks. I had to replace me air dryer with an NOS one I bought. Although I drain my tanks immediately after use, I never see any moisture. The filter was shot and the heater element was burned out. Also, you can't put tubes in the A3 tires with bead locks.

 

[Riktord]

Wehring suggested using Gemplers or other type of tire glop on the sealing surface of the split rim to prevent leaks. It is not the liquid lube but the paste stuff that prevents rim rusting and it also seals beads and should seal the oring area as well. It comes in buckets.

My bad little buckaroos, the stuff is Freylube:

"The original tire lubricant and rim rust retardant"

http://freylube.com/prema/:popcorn:

On standard rims it's great for lubrication but we don't have that issue..... could you imagine trying to shoe-horn a tire on with a hand tool? YUCK

 

[trukhead]

On standard rims it's great for lubrication but we don't have that issue..... could you imagine trying to shoe-horn a tire on with a hand tool? YUCK

Understood on the lubrication and hand tools. My thought was to glob up the cleaned area where the O-ring seals the 2 halves together to provide a substance other than RTV to fill up space between the 2 rim halves and the O-ring for that additional non-stick seal. It should make the rims come apart easier next time as well. Also lube up the bead s and areas where the beadlock band lives because they are tough to get apart.
I was going to sand blast the areas of the mating surfaces of the rims (while protecting the threads on the studs that hold the wheel halves together) and the O-ring channel as well as the area that the air stem grommet goes in to and use the frey lube after the areas are repainted.

 

[welldigger]

Understood on the lubrication and hand tools. My thought was to glob up the cleaned area where the O-ring seals the 2 halves together to provide a substance other than RTV to fill up space between the 2 rim halves and the O-ring for that additional non-stick seal. It should make the rims come apart easier next time as well. Also lube up the bead s and areas where the beadlock band lives because they are tough to get apart.
I was going to sand blast the areas of the mating surfaces of the rims (while protecting the threads on the studs that hold the wheel halves together) and the O-ring channel as well as the area that the air stem grommet goes in to and use the frey lube after the areas are repainted.

Or you could do like I am doing and have the wheels powder coated.

 

[Heavy D.]

Many people have used stuff called Syle-Glide, found at NAPA. It is a paste like lubricant. I myself used the stuff and found it quite useful on the grommets, and O rings.

 

[TNJMurray]

You don't know how lucky you are that the ctis works in the first place!! It is usually a oring, we stock most of them. Tnjmurray.com. Murco@tnjmurray.com

 

[Hoxman]

Ok.... update....

We pulled the wheel off (yeah, that was fun).... i have replaced the valve stem, the o-ring, checked 9 times for leaks in the system.... etc... Put a QD on the tire to stop air from coming out the side valve from the CTIS and it holds air.... We switched the CTIS valve onto another tire and that one held air....
We have also drained the air tank, checked the air filter (had a guy at a local big truck shop show me) and it was ok....

When I put the CTIS back on the freaking tire it went flat again.... One of the guys at the shop works on the fire dept M35s (they have two older ones) and said they used to have issues with the same thing and there was something to be rebuilt in the hub???? That fixed it for them, but when it kept happening, they took the CTIS system off their Deuces...

Any ideas and pics/instructions on what needs to be rebuilt on the hub???

Thanks!
Hox

 

[welldigger]

There are 2 o-rings in each hub that are failure prone. Erik's military surplus has them.