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1100RT Master Brake Cylinder repair question


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I sorted out my continuously on brake light only to find that the cause of the faulty switch appears to be brake fluid leaking from the master cylinder. I took it all apart and the piston would not pop out upon removing the retaining screw. I found that it would barely move back and forth and I carefully removed the piston and cleaned the bore, etc. and rubber cap. Piston and seals and bore look perfect to my eye. Since Beemer Boneyard no longer sells the seal replacement kit due to a lawsuit by BMW, do you think re-assembling the cleaned up parts might resolve what was a leaking issue due to the stuck piston? I am thinking giving it a try is worth the $100 BMW wants for the new parts.

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When mine starting leaking, I cleaned it up and reassembled. This lasted one riding season. Next time, I bought a repair kit which consisted (as I recall) of a new piston and seals. This lasted two seasons. Finally broke down last year and bought the complete master cylinder. Due to the age of the bike, I consider it permanently repaired.


That is unfortunate news about Magura/Beemer Boneyard. That is where I purchased my new master cylinder.

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to clarify my remark about Beemer Boneyard parts, they still have the seal replacement kits available, but the master cylinders a no longer for sale due to lawsuit.

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I too have the beemer boneyard seals on the bike and they have not leaked or anything. Besides that, I kinda felt the lever as being more firm, I guess that is because the seals are a little more rigid than the OEM ones, at least that's how I felt them to be.


I would say it feels like having metal lines from the pump to the calipers.



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