leaking master cylinder 70rr

[TRAMO]

put a new master cylinder on my 70RR about 2 months ago i noticed it starting to rust on the end just below the cover and it is damp with brake fluid. fluid seems to be seeping from under the master cylinder lid.gasket seem to be a little smaller than the lid,but rubber touches all the way around.i cut and inserted some stripps from the old gasket around the edge and bent the lid spring to make it compress harder. still seems to be seeping and its rusting my master cylinder.anybody out there have this problem?

 

[bee71]

Mine does the same thing,thought it was one of the wheel cylinders,but all were dry. Have a new gasket,made sure there was no rust or pitting around the top of the master,still leaks.

 

[RT4ever]

How about new gaskets?

 

[HawkRod]

I had the same problem, and ruined my paint TWICE!

In my case, I have a aftermarket master cylinder. The machining marks are really very deep, so I think that could be the cause of the leak. I plan to pull off the master cylinder and file down those machining marks to make the surface more smooth.

No guarantees, but those are my thoughts.

Good Luck,

Hawk

 

[67440chrg]

I have had the same problem for years. My master cylinder was leaking too. I bought a new one from summit with a new lid and gasket. This one seals good. I had to touch up the paint under it.