Long...MK10 plus ?

[halocline]

I can see were going to the MK20 seat in the 10 plus would would reduce the chance of o-ring failure at the HP seat.

You're talking about the 013 that sits on that shoulder in the HP side of the body and seals the seat, I guess? The side-of-the-seat arrangement on the MK20 seat probably is more reliable. On the newer MK10 kits I think they replace that o-ring with a square-profile crush washer and it works great.

 

[buddhasummer]

They do, it's a lovely red one.

 

[redacted]

Actually, the o-ring and the crush washer both work great when properly installed. The difference is you must pay more attention to the proper seating of that o-ring while the crush washer can just be fat fingered into place. I have one Mk5 that I got when a shop tech twice failed to seat the o-ring in the body before screwing in the seat retainer. I did not even change the o-ring. Just opened it up, inspected the o-ring and seating surface, and used a socket to press the o-ring into the groove in the body before assembly.