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Damaged fork seal surface, now leaking

Discussion in 'Technical and Troubleshooting Torque' started by roh, Jan 6, 2010.

  1. I did a boo boo.

    When I replaced my fork seals a few months ago, I couldn't remove the seal from the lower leg easily. I resorted to a seal puller (you know, one of those things that looks like a cross between a 'T' and an umbrella), and managed to tear up the seal surface on the lower leg a bit.

    Given the lack of easily available spares, I cleaned up the scars as best I could. Used a dremel to take down the highs, and tried (mostly unsuccessfully) to fill the lows with metal putty.

    Anyway, I though I had dodged a bullet but just yesterday I noticed an oil stain on the ground beneath that fork leg. Cleaned all the oil off and went for a ride to see how quickly it was leaking - within ten minutes oil was once again pouring down the fork leg. Lots of oil, much more than the usual ring of dirt on the inner tube.

    So, has anyone got any suggestions on a fix?

    I thought perhaps that I might be able to remove the leg and have it welded and re-machined, or even simply remove the seal and refit a new one with a whole lot of silicone/gasket maker.

    The best is obviously to buy some replacement forks, which is easier said than done. There's a whole bike on ebay atm, that has a few other parts I desire, but it's in dubbo. I'm tempted to make the trip and be done with it, rather than risk doing the job again (I replaced the seals prior to my stack, which bent the inner tubes, so this time will already be #3), but I'd love to learn of a tried and true quick fix.

    Over to you...

  2. Once you have 'cut' a seal, it's finished, and replacing it with a new one is just lining it up for the same damage, no matter how you try and avoid it.

    The tried and true fix is to replace the fork leg, re-metaling and re-chroming could end up costing a motza, whereas you SHOULD be able to get a fork leg from a wrecker (you don't say what sort of bike it is :?) for a reasonble price.

    And next time, leave the hammer in the toolbox :LOL:.
  3. As long as the fork leg isn't too badly scored, a good mechanic should be able to buff out the evidence of your presence there. Re-chroming is the next step. Buying a new one is the last resort and usually is not necessary.
  4. Used a dremel to take down the highs, and tried (mostly unsuccessfully) to fill the lows with metal putty

    I think it's a bit past that :LOL:
  5. What Hornet said, get a new fork boot from a wrecker. Check eBay too, there's drongos throwing out whole front ends for a couple hunj.
  6. Oops, the cardinal sin of Netrider - It's a 1979 Kawasaki z200. (used to be displayed in the NR 'garage' under my nic, so I forgot I had to type it...)

    To clarify, it's the fork outer leg that is damaged, not the chromed inner leg.

    I did try to buff the evidence away using fine abrasive and the dremel, and it lasted a few months before failing.

    The problem is parts availability (the reason I went for a quick fix in the first place). I couldn't get z200 forks last time, and had to settle for z250 inner legs (slightly longer but ok) and re-use the z200 outers (different caliper mountings to the z250).

    Maybe I could swap the forks for something more common (cb200?). I've always thought the bike would look good with a drum brake front...

    Thanks all for your comments, I s'pose I knew I'd have to replace it, and I'm not keen on doing the seals again only to have them fail. I'll be more careful the next time I use a seal puller, I promise!
  7. You might want to jump on austreetfighters and see if they have any ideas on what might work for a full front-end swap. Probably help to know the dimensions of your steering head...
  8. Austreetfighters, for a '79 model bike, really? Can't hurt I s'pose.
  9. Don't they have teflon or similar insert in the top of the outer fork stanchion? (My bike does, I had to replace them, metal ring lined with teflon), is it just this you've damaged? Or am I missing something?
  10. Unfortunately the z200 doesn't have any insert, just the aluminium.

    Anyway, I finally sourced a parts bike and did the swap yesterday. If there is anyone who thinks they know more than me about tearing down z200 forks, I'd like to meet them!

    Tips and tricks for anyone who might want to dismantle a similar fork:
    - Loosen the bottom allen head bolt first, with the spring still installed (to stop the cylinder turning). Use heat to break the loctite rather than applying more force - the heads of the bolts are a bit soft.
    - Use a bearing puller to remove the old seal. Works like a charm and no damage to the seal surface :rolleyes:
    - To remove the top cap with only one person, the easiest way is to put the forks back in the triple clamp, so that when you press it down you don't compress the forks.

    Feels so good to be back on two wheels!
  11. roh"
    If you cant locate another fork tube easily and cheaply, go to your local repco or similar and buy a tube of "stag jointing compound" , get a new seal and liberally coat the outer of the seal and insert.
    Clean is critical.
    Let it rest for at least a day before reassembly.
    ride happily ever after (well maybe not but worth a try).

    ok too late
  12. That's the reply I was looking for a month ago! Thanks anyway, might be useful for someone else later on.

    I'm glad it's been done properly anyway. I don't really fancy doing the job again.