97 1100RT front master cylinder leak

[omaharj]

Assuming you read the title...heh heh. It appears the rubber gasket isn't doing one of it's jobs. There is dried brake fluid (white crusty) around where the seam is. Is there a way to clean and replace? Any thoughts at all? Do I have to replace my master cylinder? Doesn't that cost more than the bike is worth? AAARGH! By the way, I've been negligent on the annual brake flush, skipped it last year and now it's June.

[AndyS]

It may be just a case of removing the 4 (M5 x 15 countersunk) screws that hold the cover on.

Remove the rubber boot (BMW part # 32722312421) inspect and clean. If no signs of damage, refit.

If damaged...replace it. Just make sure that the interface between the boot and the reservoir and boot and cover are clean and dry prior to installation.

[Tri750]

Damaged will mean the edges are flat and scalloped and the part itself will be distorted.

I also use just a hair of anti-seize on the threads of the screws.

 

Edited June 21, 2017 by Tri750

[lkraus]

This is interesting. I've never seen a white crust formed by brake fluid. Maybe I've not had the right sort of leak? Could this be corroded aluminum from water trapped under the cover but outside of the gasket?

[Shiny Side Up]

I also use just a hair of anti-seize on the threads of the screws.

Me too - the things seems to tighten up considerably all by themselves!!

[szurszewski]

This is interesting. I've never seen a white crust formed by brake fluid. Maybe I've not had the right sort of leak? Could this be corroded aluminum from water trapped under the cover but outside of the gasket?

 

Those are the words I would have used to describe the residue formed on my leaking RT master cylinder some years ago - I suppose it may not have been truly white - maybe a greyish color crystaly kind of gunk.