Fuel selector valve

[wslade2]

Going to have to admit to a degree of disorganization here. Had a lot of 337 microprojects since then with stuff scattered around including o-rings, lots of o-rings.

But...I had bought a viton o ring assortment from Harbor Freight for various uses on my 337 project. For the shaft there was a perfect fit out of that assortment but can't recall which compartment with the exact measurements. I wrote down the measurements of the original shaft o-ring as 0.5" OD x 0.4" ID x 0.05" CS (cross section). Realize that's the compressed old o-ring measurements. Nothing out of that assortment, though, fit the ports with the balls. I'm pretty sure those were 5/16" ID x 7/16" OD x 1/16" CS (cross section) that I purchased online from the o-ring store. Again, all in viton as the parts manual specifies. Sorry for being a little scattered on that now.

I lubricated the shaft/o-ring with EZ Turn fuel lubricant (grease) available from Aircraft Spruce. My mechanic turned me on to this while dealing with some fuel fitting issues and it is designed to be used in high octane fuel environment.

Speaking of the o-ring store, they've been a life saver for o-rings. A fellow pilot with a piper Lance had a leaking fuel drain/valve unit due to the tiniest worn o-ring. No body had this o-ring, not even piper could help him, except buy used $3000 hardware off ebay (no-one wants to rebuild the unit). They were able to confer with mechanic and send an assortment of o-rings around the shaft size with finally one that ended up working.