Fuel sample valve

How to keep the Cessna 170 flying and airworthy.

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Romeo Tango
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Joined: Tue Sep 02, 2003 10:32 pm

Fuel sample valve

Post by Romeo Tango »

All - I recently had a drippy sampler that needed replacing. I thought that I had gotten some crud into the o-ring and it was not reseating. Turns out the O-ring was basically disintegrated. I am pretty sure they make them out of the proper material (it's a Saf-Air product). I exclusively use 100LL, and have been using MMO for a while. I know the previous owner used 80, but not sure if AvGas ever went through.

Any advice? I replaced with like kind and it's fine now.
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Bruce Fenstermacher
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Post by Bruce Fenstermacher »

It is normal for these o-rings to go bad regardless what fuel you use. Some people keep and extra in case it lets loose at a remote location.

You can buy just the 0-ring from Saf-Air. It is a MS O-ring but on smaller than is commonly found in a parts room.

My experience is the cadmium gets worn and they start to rust over time and the rust in the set leads to leaking and hard operation. At that point it's best to replace the whole thing.
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