Rear master cylinder plastic elbow leak.

[sixinoz]

I have a leak from the plastic elbow on the rear master cylinder. The o ring is a new Honda part and the recess in the master cylinder has been thoroughly cleaned. The o ring seems to sit below the lip of the casting meaning the plastic elbow does not exert any compression on the o ring. Does the o ring seal by being a tight fit in the recess and around the plastic tube? I have bought a slightly thicker o ring to see if this cures the leak but if anyone can comment on this issue it would be appreciated.

[steve murdoch icoa #5322]

Are you referring to #20 in this schematic?
Never had a problem with a leak there and it "being a tight fit in the recess".
https://www.ronayers.com/oemparts/a/hon ... r-cylinder

[sixinoz]

Yes - #20. If this o ring does not fit tighly against the recess and the plastic part going thru it, wouldn't this cause a leak?

[daves79x]

The o-ring is a tight fit. I don't think you have the correct one. That said, are you sure that's where the leak is? If the bottom hose clamp is not pretty tight, it'll leak there.

Dave

[NobleHops]

Ya, I tried and failed to use a “close enough” oring there. Pretty sure Honda still sells the oring, I’d start there too.