captain911

Greetings Fellow 993 Owners,

The prior owner of my 993 had the Targa wheels on the car and I decided to have the original turbo twist wheels refinished and placed back on the car. (Which he included in the sale.)

I am currently losing about 5lbs of pressure every 2-3 weeks and cannot find any holes or damage. At this point is it best to have them re-mounted and balanced and checked while off the car? Would the refinishing process which only affected the outside of the wheels have caused this?

Just wondering if this has happened to anyone else.

Thanks.

Tim

2Many Cars

Refinishing shouldn't cause a leaking problem but it also won't usually fix a pre-existing problem. Are you sure the tires/wheels were good to begin with? The SOP in finding these kind of leaks is to overinflate the tire and submerge it in water and look for bubbles forming on the tire or wheel (after you've removed the wheel from the car obviously). Assuming the tire and wheel are good a common leaking area is the valve stem (particularly if they were reused) and the bead seal where the tire seals against the rim. My bet would be a bad valve stem.

cdmdriver

This may be a stupid question, but were your wheels chromed? If so, a very common problem is, the chrome on older wheels develops fine cracks and causes a slow leakage.

Van1

Are they hollow spoke wheels? If so, there is a special valve stem assembly associated with them. Perhaps the refinishing place didn't reinstall it properly or it needs a new assembly.

TMc993

One wheel or every wheel?

serval

If you cannot find any obvious holes, (too much of a coincidence in 4 wheels) it could be just the natural porosity of the metal. Try filling the tires with nitrogen. Specialty shops have the compresors. Regular compressed air is about 75% nitrogen and as high as 5% humidity. The advantages of pure nitrogen is that nitrogen molecules are larger and you tend to lose less pressure. In addition oxidization is also reduced. If you still lose pressure, then you have a leak somewhere.

Anton

Henry964

I had a similar problem with the rear wheels of my 964 (Cup 1´s 17) I tried to get them fixed but 2 different shops told me they were unfixable so I ended buying new wheels and the problem ended, no more leaks

cy7878

Cheapest to just have the tires remounted and see if that rids the problem. I had an Accord before that was leaking like yours and there was no holes either. Problem went away after the tires were off and remounted. The explanation given was that sometimes the alloy oxidaize at the interface and letting air leak. Remount the tire is much cheaper than buying new rims.

Cincy_Ron

Might want to also check the little screw in portion that goes in the valve stem. I had some new tires installed and they replaced the valve stems at the same time. Had a very slow leak in one tire and eventually narrowed it down to one of the little inserts that wasn't tightened all the way. You can pick up an insert tool at one of the chain auto part stores or even use a pair of needle nose pliers. Just a thought...

NC TRACKRAT

All of the above posts have some good ideas. B4 taking the wheels off the car, try spraying the rims, valve stem bases and cores with a mild liquid cleaner that will produce bubbles and watch closely. If that doesn't produce any results, then remove them from the car and check the inner rims. Failing that, my next guess would be porosity. It can be cured by removing the tires, cleaning the inside surfaces thoroughly, then spray painting the inner surfaces to effectively seal them. Since all four are leaking, I'm betting porosity or bad stems.

rgreeny

Have you submerged the wheels. I had a problem with a valve stem and only found it when the tire and wheel was submerged in water. It is cheap and easy. Most large tire dealers can do this.

Rob