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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Lbxpdx on September 07, 2024, 05:08:01 PM
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I just picked up a parts bike, a 1994 K75S ABS, but I think it might turn out to be a minor project bike. One thing I noticed was it was leaking fluid from below the lever of the master cylinder. I have zero history with disc brakes. It would appear from the disassembly that the o-ring was compromised with time, causing it to leak down the screw hole that affixes the reservoir to the housing. I’m wondering if my cups look okay, or do I need to order a whole rebuild kit? There is no putting on the cylinder walls.
Any and all advice is welcome.
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Well, I did some cleaning up and I’m going to get a new o-ring for the reservoir and see how it goes.
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How did it go? I've never replaced just the o-ring on other bikes (KTM/Magura) but had to replace the complete piston assembly.
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I forgot to order it. I’m placing order the order with BMW tomorrow.
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had a similar case in r1100GS - these cylinders when they go are hard to get working again - you can clean this and hone the cylinder slightly with scotch pad on a stick and a drill - goes very nicely.
ONE THING to remember though - the bore has been anodised - what youre getting now once the anodising is gone, is soft metal so the longevity might not be great. I still need to see how it goes in my case.
BUT - If the cylinder keeps leaking I am going to bore it out to oversize /there is plenty od meat around/ and sleeve it with a stainless thin walled sleeve loctited inside the bore - this will be a forever solution.
best regards
M