sdnet

All:

Ever since I filled up with air last weekend, I've been losing air in my left rear tire. In fact, it was completely flat on Wednesday morning. I discovered that the spigot cap wasn't on very well, so I filled it back up and, this time, make sure the cap was secured. It still lost air.

Then this morning, it only had about 12 PSI left in the rear tire, so I again filled it up with air, and as I was tightening the cap, the end of the cap broke completely off - thus, the cap is useless and the tire was losing air out of the spigot. I took the cap off of the front tire and put it on the back as a temporary fix. I also noticed the little red rubber "stopper" came lose from the spigot.

First, why would the front tire NOT lose air without the cap, while the rear tire DOES lose air?

Secondly, this sounds like something that I should probably have done by a shop, right? Is it possible to buy replacement air spigot caps? Even if I can do that, I'm afraid that the problem goes beyond the cap itself.

Any thoughts?

TraceZ

If it is leaking at the valve stem It could be some dirt in the valve core.

Get a new valve core and see if that fixes it. Do you have a valve core wrench? If not, get one with the new core. They are cheap.

87SAM

Sounds like you just need a new valve in the valve stem. The caps are not meant to seal air in the tire.

sdnet

Thanks to both of you for the responses. I quickly Googled this, but haven't come up with an actual procedure on the repair. Unfortunately, I have very little mechanical skills, so I need clear and concise instructions. Would anyone here know of a published procedure for performing this work?

Thanks much.

zee oh six

Always Give the tire a good looking over (remove wheel from car) and inspect for the dreaded drywall screw.

sdnet

Yeah, I had considered that as well, as I live in a new area with lots of construction going on. The reason why I assumed that it wasn't something as simple as a screw or a nail is because this only happened after I filled up with air and put the valve stem cap back on. I've never had a problem like this before. It could be one big coincidence, though.

v.vet's Z06

Owned my car 3 1/2 years and have had 5 nails/screws in my tires.

87SAM

Stop by most any local tire shop and they will likely replace the valve for free. It's a no biggie (the tire does not need to be removed).

zee oh six

Low air pressure = heat=bad at any speed > 5
Corvette = speed > 5

hotwheels57

Return tire or drive the car to a tire shop for inspection of penetrating foreign objects allowing air to escape. Or in the alternative if no foreign objects are located, for a professional replacement of valve core (threaded one way valve inside the valve stem, covered by the screw on cap).
Or another alternative, jack up car using lift pucks at the suggested lift points and spray a soapy solution all around the tire, watching closely for tell tale signs of air bubbles. Mark the hole with a grease marker and drive to a tire shop. Or remove the tire for professional repair.
Or, while the car is supported on a jack/stands, use suggested inexpensive tool to remove the valve core, screwing it out of the stem counterclockwise. Take it to your favorite tire store or automotive supplier and get another core. Thread the core firmly into the stem clockwise. Air the tire to the suggested psi @ probably 30# cold. Replace the valve cap.
A very remote possibility is that you have a tire separating.

sdnet

Thanks all for the suggestions...I think that I'm going to drop by Discount Tire on the way home and get the valve stem tested and replaced if necessary.

HMannini

I had a leaking O ring, I tightened down the valve stem, "Gently" several times until it stopped leaking........

Bugaboo

odds are it'll be no charge.......good outfit.

rapid robert

I had bought chrome value caps for my car. They had a red plastic stopper inside the cap. When I would tighten the cap the red plastic stopper would push down on the value stem releasing the air. I removed the red plastic and had no more problems.

gimme5

Remove wheel/tire assembly.

Inflate.

Smear soapy water (or just water) over entire tire (entire tire; that's funny) and valve.

See bubbles.

Make bubles stop happening.

— Could be base of valve assembly —

Send check to...

LoneStarFRC

That's where my bet is.

sdnet

Would those here agree that the fact that air leaks out of the value stem without the cap on generally indicates a problem with the valve stem? While another puncture could certainly be present, that other puncture couldn't cause the value stem itself to leak, correct?

TraceZ

That is what I was thinking. A puncture in the tire would not cause air to leak out the valve stem.

tiojames

Caps do nothing but keep the debris out. Could be the valve core, a split valve stem, some type of injury to the tire itself, or a leak where the tire seals on the rim. Take the wheel off and run some soap suds around it.

RonJ

Find a 13 year old kid with a bicycle. He can probably replace the valve for you! Same valve, believe it or not.

RonJ ...