R100RT Front Brake Master Cyl Leak

[fotofreak]

Dumb question. I have lost some fluid and seen drops on fairing yesterday Fri Apr 2. Bango connection is dry. I am currently on the road.

I found a lot of "Brake fluid Mud" in all areas which implies prob is not new. Yesterday first notation of drops. System flushed in Summer 2009.

Now for dumb question. Do the three screws hold the seal of the MC reservoir at top and bottom?

I had not tightened "hard" last summer when rebuiling calibers, discs, etc. I was afraid of damaging plastic reservoir. Today when checking torque, one screw might have been looser than others though not very loose. After tightening then other two also needed snugging. Then I cleaned everthing and tried really hard to create leakage (static test only). NO LEAK. Shortly I'm going to auto parts store to get spare fluid. That ride will make the test more dynamic.

 

[jforgo]

There is also a screw which holds the master cylinder reservoir to the casting when you have the lid off. It is the one on the bottom, in front of the round part where the plunger goes. These screws hold the reservoir down, which is then sealed by an oring on the bottom of it.
I had one start leaking after I flushed the system, but that was from the plunger itself. If you decide to do this, also get the reservoir bottom Oring - oddly enough it doesn't come with the plunger kit - yet I cannot see not replacing it simultaneously.
If your seepage starts from where the plastic mates with the metal, then this oring would seem to be the culprit.
Where are you?

 

[fotofreak]

Tucson, AZ
After crosstown trip and sitting in sun several hrs, the leak started again. Brake fluid has a mind of it's own. Checked my carry along spare parts. I had a spare piston kit. Somewhere and I can't image how, my senility decided that front and rear was the same piston kit. After removing the MC and disassembling, I found the error of my thinking.

So I need a piston kit and it is Sat. Iron Horse opens Tue. Guess I need to check other options.

There must have been water in system at some time in spite of annual flush. The spring is rusted to piston. I noted during last summers caliper build a lot of rust in that area. But to best of my memory they had never been rebuilt since I bought the bike in 1982.
I picked up the o-ring at Iron Horse Motorcycles this afternoon. Just in case. Thinking that I really had it stopped by tightening the 3 screws.

 

[ISAMEMON]

if you have that much rust inside on the spring, better check the bore good . any scoring or rust will eat up a new seal in time

 

[fotofreak]

MCyl now ordered. Thanks for responses

M Cyl now ordered. Thanks for responses. Tucson Dealer will order today and I'll get part early Tues. That's as good as I can hope for.