Tire going flat but no bubbles???? :)

[zbeest]

So I get home from work yesterday and notice the front drivers tire looks a little flat. Get the gauge out and it's about 13psi! Hmmmm, check the others and the other front is about 26psi and the rears are bout 34... pump them all up to 40 psi and check the bad tire for obvious signs of a nail and find nothing....
Visual check when I wake up this am and they look ok so I drive off to work and leave it for the day...Come out and notice that its low again so get the gauge out and it's reading 10psi! Drive it to the closest gas station pay my 50 cents and inflate to 40 psi again.... drive it home ( less than 1hr or 60km) and find it's pretty much flat again.... WTF.....Take rim off and inflate to 40 psi and then dunk it in a kiddie pool and watch for bubbles......Watch and watch, give it poke, flip it over ,play with the stem, flip it over again and watch it some more. Still no %#$! bubbles!
Close inspection for rim cracks or nails and find nothing...
They are Viper 20 x 9" chrome rims with Toyo Proxes 245 tires if that makes a difference. I can't figure out how the hell I can lose 30 psi in less than an hour and NOT see any damn bubbles.... Ideas?
Will see how it is tomorrow morning again.....

[Zoban]

Might be a bead leak that only actually leaks when there is weight on it to stress the bead seal..

Had a similar issue with my PT after a few re-seal attempts I got ticked off and used one of those crappy tire cans for road side (only a portion of it) and went for a drive .. never leaked again..

[DonH]

Or it could be something stupid.

Could the valve stem cap be pushing down on the valve stem letting out air? Some caps have a little O ring inside, when dislodged it will cause air to escape.

[Mr. Magnum Man]

Its me I sneak over and let the air out when your not looking. Seriously itc ould be the bead it can shift with the cars weight on it over inflate it to 60 lbs and spray with a soapy water mixture. Return to proper pressure before driving.

[Daytona 226]

I recently went through this on my other car. It was the bead. Tire place shifted it slightly, and all is good now.

[FloridaRT]

Probably the bead seal, could also be some corrosion where the tire seals against the rim.

May have to take tire off of rim, inspect rim seating area for corrosion and remount tire.

Bob

[zbeest]

Well, I went out this morning to check the pressure as it "looked" ok. Went to unscrew the cap and ended up pulling the guts of the valve out! Looks like the glue that bonds the brass part into the rubber has failed. I had to jam it back in to inflate enough inorder to get a jack under the car.... Swapped a winter rim/tire over and dropped the Viper off to get a new valve asm installed. That will also take care of any bead issue..... I don't think the valve was leaking, unless the cetrifical force of the spinning wheel was somehow contributing to it....Either way, it's getting a new valve and the bead reseated....Just hope they don't scratch the rim!

[FloridaRT]

The valve stem core "screws" into the valve stem, no glue is used.

Need a special valve core stem tool to screw it back in.

I have a couple in my tool box.

Bob

[zbeest]

I can assure you that this one was glued in...
I stood there holding it in my hand as the tire went flat in about 5 seconds.....
This must have been a cheap stem or the part that you were refering to was part of another assembly -that fits into the rubber part....

[CREMATOR]

huh, maybe when you had them installed some numb nutz messed it up and tried to put some kind of sealer in there to get it by for a while.

[stitchmonkey]

I have the same, almost same problem. One of my rears loses presure over a few weeks.

[4DEATER]

I have the same, almost same problem. One of my rears loses presure over a few weeks.

I had that with my tires when they mounted them at the show in Columbus. It was the needle valve. It was over tightened. They have an actual needle valve torque wrench for that. I didn't know that.

[zbeest]

Seems to be fixed now.. Been fine for past couple of days.... Could have been the bead but the valve was toast for sure...

[Mr. Magnum Man]

Wow this thread still on the front page. getting more life then my Conti's. Glad you found the problem.

[Big RobsR/T]

My front tire slowly loses pressure over a couple weeks as well. Im not sure what it is. I had a blowout in Louisiana and had to get some cheap tire at a store in a small town so I could drive back to Texas. Funny because my previous tires I had on for 35000 miles and they never lost pressure.