Master Brake Cylinder Leak - Advice Please

[Ron Jarvis]

Ken H re-taught me how to bleed the brakes last weekend. (By the way, I would have contacted Ken first, but he's away at a conference). Things went just fine, as I insisted he let me actual do it all with him close by and giving regular advice. By no fault of his, I over-filled the master cylinder, but could get the 4 top plate cover bolts on without any fluid leak. Three days later, I discovered that I have a leak (no, it did not get the paint!) that appears to coming from the round rubber seal that is actuated by a plunger/sping, although I'm not sure that is the source. Questions: (It's a '96 RT) Is there a part or parts that can be replaced to deal with this, if it's a "typical" master cylinder probelm? Is it a DIY fix? Should I just replace the master cylinder and get it over with? ANY advice will be welcomed. When I bought the bike in April of '04, I noticed there had been some kind of leak, but it's always been dry under my ownership.

 

Regarding how much of a leak, when I first removed the plastic brake lever cover, it had about a teaspoon full of fluid which could have easily been from my over-fill. Since Thursday, I check it twice a day and find about 2-3 drops in the plastic cover that "migrate" under the master cylinder. Obviously, I'm not riding until I fix it. Oh yes, I've had one person tell me not to worry about it and that it will or should stop leaking. That would be great. One drop of brake fluid on the paint is unacceptable, however. Thanks. Ron

[smiller]

You might have just forced some fluid past the seal when you overfilled the master cylinder in which case it might stop leaking all by itself, or it may be leaking for real (not an uncommon problem.) If so there is a rebuild kit available that will take care of it (p/n 32-72-2-332-037), cost is about $40.

 

Search for this topic and you will find several threads describing the rebuild process, it's pretty easy and IMO the way to go unless you discover any irreparable damage or corrosion inside the bore.

[Ron Jarvis]

Thanks very much - I'll look it up tonight. Ron