hotrod180
FRIEND
Port Townsend, WA
There was a Bonanza Master cylinder that got acting goofy. It would bypass half the time. An old A&P changed every O-ring in it. It still was goofy. While they, the owner and the A&P, went to lunch, I took it apart again. There was one harmless looking washer with rubber on one side that looked like it acted as a one way valve. That washer didn't get changed. We studied the parts manuals until we found a parts kit with the mentioned valve washer, ordered it, changed all the stuff out again, and the master cylinder worked OK. jrh
FWIW Cessna calls this washer/o-ring combo a lock-o-seal.