"Why, I have no idea who put that o-ring in there. It must have been done
before I bought the airplane. (TM)"


Jim



These are MS28775-329 rings. The rubber is an ancient type,
probably around for 40 years or more, and while there are much better
O-rings on the market now we can't use them since Cessna does not
approve them and no one, as far as I know, has done an STC on a better
ring.