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Re: [T3] glycerin rubber treatment

<x-flowed>Good info Jim. I knew there was something out there with the proper info in it.

Isn't Rubber a Petroleum product? I thought there were oils in it and that the Vaseline replaced lost oils that time took away? It sure acts like it when applied.


There are (obviously) some types of rubber which are fine with petroleum
products, but most are not. The worst petroleum offenders are the most volatile
ones, like gasoline. Vaseline is a rather heavy, non-volatile, compound which
whose effects should be minimal.

On type 3s, it is clear that the rubber oil filler bellows is quite happy with
oil, but if you take a look at the rubber "gasket" under the "base" (where the
dipstick screws in) is a perfect example of a rubber that is NOT compatable
with oil. Those should have been made from a different material, but they

The bad effects consist of the petroleum compound soaking into the rubber and
causing it to swell and soften. I suppose that a limited amount of this, like
you might get with vaseline, might even give good results. But most of the time
there is also a long term degradation of the rubber compound.

My resource for this is the Parker O-Ring Handbook. It is an extremely useful
compendium of information on the properties of various rubber compounds and
their compatabilities with lots of various fluids, as well as a listing of all
standard US sized O-rings and design specs for designing proper O-ring grooves.

Don't ever pass up the opportunity to grab one of these.

Jim Adney

List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org

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