Originally Posted by
dedwards0323
I've never changed that O-ring either. Didn't know there was even an O-ring up there. Never took the assembly apart. I just replaced the other O-rings, slid a new fleece filter onto the shaft, made sure it was seated properly and re-installed the filter assembly. Always torqued the cap to proper setting. Would be curious to know what risk we're taking by not changing the #4 O-ring. Does the shaft just pull out of the cap?
From what I've read on the MB forums, no one ever changes that o-ring. It has never been reported to leak, and those that did change it report that the stem does not like being taken apart and put back together. It easily wears down the connection, causing it to break down and become unusable. Consensus is to best just leave it alone.