Tires/Brakes Concern

[gprime85]

I've noticed that if I fill up my tires to proper inflation, after about a week (of local driving, 100-150mi) I lose anywhere from 5-10 psi in my rear tires (2-3 psi in the front). Is this normal? The tires came with my car so I'm not 100% on how old they are, although I've got a good 60-70% of tread left so they can't be all that old.

Could this be an indication of another problem say, with the brakes since its the rear tires that lose the most? And also, I notice that when I slow down and brake, my car pulls to the right enough where I'm conscious of it and have to turn the wheel to counter act it. I'm thinking maybe my pads are rubbing on the tires?

[MantaGreen97]

No losing that much pressure in a week is not normal. Since all the tyres are losing air, my first guess would be that the tyres are leaking slowly at the rim bands. If it were one tyre it could be a slow leak from a tiny puncture or bad valve stem, but since it's all of them that probably isn't the case.

If they are leaking around the rim, all the tyres will have to be removed and the wheels cleaned up (the surface where the tyre beads seat) and then the tyres re-installed and balanced again. Best way to find out if/where they are leaking is to take one wheel off and place it in a large tub/bucket filled with soapy water (the entire wheel has to be submerged). You'll see little air bubbles coming from the leak. If you don't see anything after looking for a bit, pull the wheel out of the water and look for bubbles again. If, upon letting it dry a little, you see streaks coming from the rim where the tyre meets, then it's definitely leaking around the rim and the tyre(s) will have to be removed as mentioned above...

The brake problem is likely separate and unrelated. I can't fathom how brake pads could ever touch tyres unless the tyre was flying off the wheel or something, lol. The pull when braking could be caused by one of a few things such as a sticking/bad caliper, warped rotor, worn wheel bearing, etc...

[daman]

you'll have to break the tires down off the rims and buff up
the rim lip then remount..

[Crackers]

Yup, clean the rims and once they are off, replace the valves.

As for the car pulling and the brakes; car pulling could be the tires, and could be a brake, could be an alignment.

Start with the tires, move from there... let us know the result.

(ps. it is not uncommon for a valve (or many) to leak, or for the rim to corrode; mag or steel.. so don't feel bad!). Also check to be sure that no kids are letting air out of your tires!!!

[daman]

Originally posted by Crackers
replace the valves.



yes yes yes :)

[rixGAphx]

You don't say what kind of rims you have.

My '96 came with a set of the Pontiac 3-spoke cast alloy wheels, in body-matching white.

One of the rims leaked.
Not the tire, not the bead, not the valve stem.
The RIM!!
Not crakced or bent, but porous.

Would lose about 5 psi per week. Never showed up on a leak test.
Tire manufacturer wouldn't replace the tire 'cuz no damage or leak could be found.
Installed new valve stems. No change.
I had the tires swapped onto different corners. Problem didn't go with the tire, it stayed with the rim.
I was convinced it was a neighborhood kid, until I moved that rim to another corner.

It's rare, but cast aluminum CAN be so porous as to leak.
And, steel wheels can leak at the weld, if they corrode enough.

just some odd thoughts,
-Rick

[SE2000]

Probally bead seal or valve stem. Easiest is to check the valve stem, just spray soapy water with the little cap off and where the valve meets the wheel. Be sure to flex the valve back and forth when you are spraying. Next If you can get a bucket or bathtub to submerse the wheel into, at least part way and the water covers the bottom of the wheel also, rotate the tire slowly until you see bubbles. Tires stored flat on rims are prone to rust. If you find the bead leaking, you can try removing air from the tire, pressing down where the leak is and cleaning the bead. Next get some bead sealer, I buy NAPA's in a quart can, and use its brush to get down into the bead. Refil tire and check your progress. You won't have to have the tires rebalanced because the tire never gets rotated on the rim. I still do this even though I have my own tire machine and balancer