Weeping Brake Master Cylinder

[Disaster Area]

Hi all,
I've noticed that the front brake master cylinder is weeping. I seem to remember reading a thread about a repair kit, but using the search function for brakes, master cylinders etc gives hundreds of results, none of which is the thread I remember.

Did I imagine it? Can anyone shed any light on this problem and the repair kit process?

The bike is a 1100GS.

Cheers,
DA

 

[Steptoe]

You need master cylinder piston and seal kit. Available from motorworks or james sherlock for £20ish.

Repair procedure requires the removal of the brake lever and one small grub screw in the side of the master cylinder and the piston can be removed. Replacement is the opposite

Do it with the master cylinder angled upwards and you don't even have to bleed the brakes. Just a few gentle pulls of the brake lever and all the air gets expelled into the master cylinder.

 

[Disaster Area]

Thanks

I assume that this is a fairly common thing then?

Will get one ordered ASAP.

Cheers,
DA

 

[waterloo700]

Don't know how common it is but mine went at 60k. Repair kit worked a treat.

Incidentally the rear master went a year later - as far as I know there is no repair kit for these.

 

[Disaster Area]

Further investigation...

Hello all,

Yesterday I peeled back the rubber bellows that goes around the piston behind the lever. The lever and the surrounds didn't have any visual evidence of a leak.

My question is: could it be leaking from round the back where I couldn't see or, is there so where else other than the piston?

I don't know what the structure of the lever and cylinder are, so I don't know where potential leaks could be.

Thanks a lot,

DA

 

[Disaster Area]

I've just put the new piston onto the bike.

The old one came out with a pop and a loss of fluid, so I've topped up the reservoir, pumped the lever a few times until fluid fountained up.

The one question I have is: Did everyone find fitting the new rubber bellows a pain in the neck? I tried for about an hour before just settling it for as good as I could get. Is there a knack to it? Will it matter that it doesn't sit on the notch on the plunger that comes off the lever?

Anyway, I've tied the lever back and I'll leave it for a few hours and then try the brake - very gently!