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Thread: Master Cylinder rehabbed '88 K75C

  1. #1
    Registered User rall275's Avatar
    Join Date
    Apr 2017
    Harrisburg, IL

    Master Cylinder rehabbed '88 K75C

    Thanks to Lee 98 I rehabbed my leaking master cylinder. I'll share a few photos but first a short narrative.

    Only issue I had was separating the master cylinder from the bike after removing all the screws necessary because it had stuck from crud and had to be tapped apart. The piston was in good condition, the rubber was intact. The bore looked good, but I cleaned it out anyhow. The throttle chain/cam needed to be cleaned out and relubbed, as the old lube was dried out or absent.

    Reservoir was leaking from the o-ring underneath. Replaced this, the reservoir, cover, and rubber flap inside. I repainted it and it has worked well and not leaked.

    1. crusty brake fluid on master cylinder
    2. cover off. Note lack of lubrication
    3. piston pulled out of MC. Was in good condition
    4. Master cylinder after cleaning/painting
    5. old reservoir/new reservoir. Note crusted and shrunken o ring on original
    6. Put together without the cap or grip on
    7. Have the cap and grip on now. mirror still not attached
    8. MC with attached reservoir all shiny and painted

    I changed front pads, added Spiegler brake lines, removed/cleaned/rehabbed throttle body, replaced the cooling fan and rehabbed coolant system. Maybe I'll post photos of those projects if anyone is interested.

    Attached Images Attached Images

  2. #2
    Fortis Fortuna Adiuvat Omega Man's Avatar
    Join Date
    Jan 2010
    Great job

    Itís nice to have projects so well documented.

    "You can do good or you can do well. Sooner or later they make you choose." MI5
    Mod Squad
    2009 F800GS 1994 TW200

  3. #3
    3 Red Bricks
    Join Date
    Jan 2007
    Pleasanton, Ca.
    The seals on the piston are worn. They might still be sealing, but they are supposed to have a very sharp lip on both seals. They right had one looks much more worn than the left hand one which is also worn.


    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

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