master cylinder rebuild 86 nighthawk

starting with the sight glass, pulled it out with an 1/8" hole and a screw.








cleaned up the bore and installed the new glass with new O-ring. these are the standard 18mm that Honda uses in a lot of applications.











its a press fit, much like a shaft seal on an engine.

ran into an issue with the piston from 4into1 being a little too big, could not get it into the bore.
i don't think i should have to put a new part in the lathe to get it to fit.





so i cleaned up the original and swapped the seal off the new one even tho the old piston was .004 under the limits.



you can see the rust ring on the head of the old piston where someone put it together backwards. yep, the other seal was at the outlet of the shaft.
not sure what that does for braking power.







i ended up getting the 4 pack of sight glass, so if anyone needs one you can PM me.

Excellent write-up and pictures. Now a sticky