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Got the Blues? (As in Stains on Your Floor?)

By Ralph Inkster, EAA 448193

June 2020 – Replacing the seal in a gas tank drain is an easy five minute job, after draining your tank of course.

All you need is a small diameter drill bit, a sharp tool like a dental pick, and the proper replacement o-ring. After the tank is drained, press the valve open and insert the drill bit to hold it open. Then remove the old o-ring with the dental pick and replace with a new one.


Replacing the fuel drain valve o-ring.

Make sure you get the right o-ring size. The SAF-AIR CAV-170 has a small o-ring on the stem and another larger one on the base where it seats against the body of the fuel tank. According to SAF-AIR you'll need Viton Compound M83248/1- 06 or MS29513-06 for the smaller size and -12 for the larger o-ring. Both seem to be Viton (fuel resistant synthetic rubber) mil specs. The only one you'd need for a valve like the one is the picture is the -06. You can replace them both for less than $1 so it's good to have spares. Thanks for the tip about the dental pick Ralph, great idea. — Ed.

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