R1100GS Rear Caliper Rebuild?

Discussion in 'GS Boxers' started by m1sandman, Mar 2, 2021.

  1. m1sandman

    m1sandman Adventurer

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    Howdy everyone,
    I’ve got a rebuild kit in order for my rear caliper and wondered if anyone had a good DIY on it? I searched and couldn’t find anything specific to the R1100 rear.
    Thanks!
    #1
  2. mouthfulloflake

    mouthfulloflake Not afraid

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    Hmmm I recall doing my fronts in early 2018

    Not sure I have ever rebuilt the rear though.
    #2
  3. Whale Rider

    Whale Rider Been here awhile

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    Hope this helps
    upload_2021-3-4_11-46-30.png
    #3
  4. lewisjr1

    lewisjr1 Long timer

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    As above, the "rebuild" procedure is merely replacing the seals. There's nothing particularly specific to the 1100 model rear brakes, as the process is similar for nearly (if not) all BMWs from that vintage, to include their cars.

    As with much in life, cleanliness is important here. Note also that brake fluid will mar painted, surfaces, plastics, and probably teeth. Brake clean from a can can do the same to plastics. So be careful with drips, overspray, etc.

    If this project is time or tool constrained, any decent shop can do the task with the caliper on their bench in under 30 min.
    #4
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  5. m1sandman

    m1sandman Adventurer

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    Thanks @Whale Rider, that exactly what I was looking for. I’ve done lots of auto caliper rebuilds before, just never done a motorcycle before and wanted to see what I was dealing with before I took it all apart. Thanks for the walkthrough @lewisjr1
    #5
  6. mouthfulloflake

    mouthfulloflake Not afraid

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    also Brembo will tell you not to take the caliper halves apart because the are matched machined whatever.

    I did my fronts without issues, I assume the rear is just as easy and simply.

    kit came with new pistons, probably didnt need them but used anyway.

    get it all super clean, replace all O rings, new seals on the pistons ( lubed well with brake fluid)

    its a VERY messy job.
    but pretty simple over all.

    make sure and clean the bleeder path and screw.

    removing pistons can be exciting, especially if using air pressure.

    :photog
    #6
  7. neppi

    neppi Long timer

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    Grease press is easier for your eyes if the pistons are stuck. Flying pistons might hurt. It makes a mess, but you’ll clean up everything anyway.

    I had to cut my rear brake pin, the one that holds the pads, in three to get it out. Other than that, it was easy peasy.
    #7
  8. jigginjim

    jigginjim Anyone for a Guinness?

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    Use this opportunity to replace slider pin and bleed nipple with stainless items. You should be able to pop the pistons out before you remove the flexi hose by operating the brake pedal. If one piston is a bit stuck I use a G clamp to make sure both pistons are progressing evenly. Use a pick to pull the old seals and replace with a bit of brake fluid to lubricate. Then pop the pistons back in. It is a messy job. If you live in a wet area where a lot of gunk gets deposited around the caliper I would recommend the use of a ceramic lubricant like Ceratec. Rear caliper is in one piece so no splitting required. A point to remember is that the pistons hardly ever need replacing, just the seals (this was my experience following ten years of 1100gs ownership and riding all year in all weather).
    #8
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