F800GS - stripped side rack mount point

Discussion in 'Parallel Universe' started by jlpp, Nov 25, 2011.

  1. jlpp

    jlpp Adventurer

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    What are the options for dealing with a stripped side rack mounting point thread as seen in the attached picture. When I put the bolt in it gets to a certain depth and runs up against the stripped threads and then the entire circular unpainted metal threaded hole starts to rotate. The fact that it rotates makes me wonder whether this circular threaded mounting point is meant to be replaceable. Never tapped (threaded?) a new hole before but I suspect the fact that this thing rotates will make it difficult. Any ideas on how to proceed?

    Thanks a lot for your help.

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    #1
  2. jlpp

    jlpp Adventurer

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    Here's a closeup shot.

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    #2
  3. fastredbike

    fastredbike out riding

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    this seems pretty common, these fasteners are replaceable. Your dealer can insert new ones or some people have done it themselves - there's a special tool you need. There's a big-box hardware store here called Princess Auto (the Canadian equivalent of Harbor Freight, I think) that sells a DIY bundle with various sizes of threaded inserts and the tool you need to switch them in and out. Harbor Freight may have it too.

    good luck
    :thumb
    #3
  4. flying.moto

    flying.moto Earthbound Misfit, I

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    Looks like a rivnut to me. A common aircraft fastener. I dont favor them for that exact reason, when they get loose they spin. Replaceable, easy to install but they do require a special puller. http://en.m.wikipedia.org/wiki/Rivet_nut
    #4
  5. jlpp

    jlpp Adventurer

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    Thanks. Is this the tool you're referring to?
    http://www.princessauto.com/worksho.../2925204-sae-threaded-insert-installation-kit
    #5
  6. fastredbike

    fastredbike out riding

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    #6
  7. tofire409

    tofire409 Geared up and ready.

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    #7
  8. jlpp

    jlpp Adventurer

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    Thanks all. I'll let you know how I end up fixing it.
    #8
  9. jlpp

    jlpp Adventurer

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    Well, got step one done: removing the old rivet nut (see photo). I had to use a Dremel and cutoff disc to grind it off as delicately as I could. I couldn't drill it out because the rivet would just spin freely, never allowing the drill bit to bite. Unfortuantely this put a few scars into the frame. This looks much worse in the photos. It's really just scratches in the powder coat/paint.

    I went out to Harbor Freight to pick up a threaded insert riveter kit (http://www.harborfreight.com/45-piece-threaded-insert-riveter-kit-1210.html) but this only rivets sizes up to 1/4-20 (standard sizing) whereas the original rivet is for an M8 bolt (metric sizing) and I was concerned that the rivet wouldn't hold well enough in the larger frame hole.

    Soooo, does anyone know if BMW has a named/numbered part to replace these rivet nuts? And maybe a tool?

    Thanks,
    Jeff

    Attached Files:

    #9
  10. LukasM

    LukasM Long timer

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    Do a search on rivnut, another member had the same problem and had it fixed by his dealer, I think with an official tool.

    Alternatively every machine shop should have a rivnut setting tool. Ask them to coat the outside of the nut and the hole with epoxy for some extra insurance against this happening again.
    #10
  11. machinebuilder

    machinebuilder Long timer

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    i've set many of them without the "correct" tool.

    screw a nut all the way on a long bolt of the correct size,
    put a washer next to the nut,
    screw the rivnut on the bolt
    insert assembly in the hole,
    hold the bolt with a wrench and tighten the nut,
    this will expand the rivnut, when its tight remove the bolt


    the riv nut works like a pop rivet, they're ok but don't over tighten anything in them because they will spin
    #11
  12. Kaw4Life

    Kaw4Life Busted Adventurer

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    I wouldn't worry about the bolt holes, but I would REALLY worry about your brake fluid. :eek1
    #12
  13. grndzr0

    grndzr0 its Ground Zero

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    Kinda looks like egg yoke...
    #13
  14. jlpp

    jlpp Adventurer

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    Uh oh. I had a 12k mile service at Bob's BMW a couple weeks ago. They would have checked the fluid then. Maybe the reservoir plastic is discolored. I'll check though. Thanks for the heads up.
    #14
  15. zaner32

    zaner32 In over my head

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    I had the same issue with mine this past summer. There's a thread here somewhere...

    I chased the threads SLOWLY with a tap while holding the sides of the rivnut with a pair of vise grips on just tight enough to hold. I didn't want to collapse the rivnut.

    It eventually chased right through after a few beer and some choice french canadian swear words.

    I then threaded a nut and put a washer on a bolt, inserted the bolt as farw as it would go by hand. I then backed up the nut against the rivnut while pushing the bolt in. Once the washer touched the rivnut, I kept on going for 3/4 of a turn, and Voila! the rivnut was back in, and everything held on great for the rest of the summer.

    Got the idea here...
    http://fjr1300.info/howto/rivnut-tool.html
    #15
  16. puckinet

    puckinet Safety third

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    a rivnut kit runs about $70 bucks with the tool very handy and nice thing about the tool is you can go back and snug them up when they get loose. After inserting one chase it with a tap to make sure the threads are nice and clean.
    #16
  17. jlpp

    jlpp Adventurer

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    Thanks all for the suggestions. I wanted to post back to let you know what ended up working the best for me, after a few failed attempts.

    Two closest BMW moto dealers estimated $50-$300 for removal of stripped rivnut and replacement rivnut with installation. Harbor Freight was the only local tool shop that sold a threaded riveter but it didn't go up to M8 size. In the end, inspired by http://www.youtube.com/watch?v=mzZc9FZ-pfo, I figured that I'd try without a riveter. The M8 rivets themselves didn't seem to be available locally either so I ordered a bag of five from McMaster-Carr: http://www.mcmaster.com/#catalog/117/3269/=f8lszh

    Parts:
    1 x steel M8-1.25 rivnut (18-8 stainless steel M8 knurled body, 0.7-3.0mm material thickness, 11.1mm hole size)
    1 x 12x1.375 inch Simpson Strong-Tie heavy duty strap
    1 x 3 inch M8-1.25 threaded steel rod (no head)
    2 x M8-1.25 nuts
    2 x sturdy washers that fit snugly on M8 rod

    Tools:
    Pass-thru socket wrench w/ socket that fits over two stacked M8-1.25 nuts (may be able to do this with a regular socket and a shorter threaded rod)
    Sturdy vice (or hammer + hard surface)
    Drill w/ 5/16 inch metal bit

    Steps:

    1) Used the heavy duty strap to make an "anvil" against which the face of the rivnut is pressed while it's being compressed. The face of the F800GS's side rack mount rivnuts are depressed into the plastic wheel well by a couple millimeters. For this, the anvil approach from http://fjr1300.info/howto/rivnut-tool.html had to be adjusted, actually bent, to work. I measured the width of the depression to be about 1 inch and used a JawHorse clamp (similar to a vice) to make two 90 degree bends, one about an inch from one end of the strap and another, bent the opposite direction, about an inch in from the first bend. Actually, I started with the second bend.

    2) Drilled a 5/16" hole where the center of the hole is 3/8" from the end of the strap, on the bent end.

    3) Screwed each of the two M8 nuts so that they are near the middle of the rod.

    4) Placed one washer onto the rod so that it rests on one of the nuts.

    5) Put a dot of lubricant on the second washer and then placed it, lube side first, onto the rod sandwiching the lube between the two washers.

    6) Slid the rod through the hole in the anvil so that it rested on the washers.

    7) Screwed the rivnut all the way onto the anvil end of the rod.

    8) Let the anvil and two washers rest on top of the rivnut and screwed the nuts so that they are fairly tight against the washers but arranged so that the socket can fit over both them together.

    9) With everything tightened down, took this thing out to the bike and put the end of the rivnut into the frame hole and the "handle" of the anvil perpendicular to the frame.

    10) Put socket wrench over the two nuts and tightened, holding the anvil to prevent it from rotating, until there was strong resistance, indicating that the rivnut is not spinning against the anvil and is now compressing. Continued to tighten until the nuts made two full rotations (three rotations may be better but I was paranoid about stripping again).

    Rivnut:
    [​IMG]

    Strap:
    [​IMG]

    Loose stack:
    [​IMG]

    Tight stack:
    [​IMG]

    Zoomed out tight stack:
    [​IMG]

    Socket with tight stack:
    [​IMG]
    #17
  18. JRWooden

    JRWooden Long timer

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    Outstanding thanks for the tips :clap
    #18
  19. tofire409

    tofire409 Geared up and ready.

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    Nice job :thumb
    #19
  20. BcDano

    BcDano One Lucky Dude

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    Thanks for the post, I had this issue.
    #20