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  1. #1
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    Leaking front shocks

    Alright, so I just bought my first nice mountain bike, and it's a 2001 Stumpjumper FSRXC Pro.
    Spec sheet here: http://www.bikepedia.com/QuickBike/B...5747&Type=bike

    I bought it used off ebay, and it was described as having a leaky "front fork" which I just take to be the shocks. Any way to patch that up nicely without spending a lot of money? I am fully capable of difficult repairs, I just gotta know what to use and what to look for, so if I am incapable of fixing it, I can at least understand and know what to ask my lbs to do.
    Last edited by rpg711; 05-25-2010 at 04:46 PM.

  2. #2
    Fat-tired Roadie
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    The fork probably needs a rebuild. Real World Cycling makes a nice seal kit for a lot of different forks and also publishes instructions for rebuilds.

    http://www.enduroforkseals.com/id8.html

    You can probably also find a service manual on the Rock Shox web site.

    The SID has a reputation for needing frequent service. I don't own one and can't comment on whether or not that's true or how often it needs to be done.

    Depending on where the problem is, you might need to order a part, you might need to scour the internet for it due to your fork's age, or you might be able to get something at a hardware store. Kind of depends on whether it's an oil or an air leak, and how lucky you are.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  3. #3
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    Quote Originally Posted by AndrwSwitch
    The fork probably needs a rebuild. Real World Cycling makes a nice seal kit for a lot of different forks and also publishes instructions for rebuilds.

    http://www.enduroforkseals.com/id8.html

    You can probably also find a service manual on the Rock Shox web site.

    The SID has a reputation for needing frequent service. I don't own one and can't comment on whether or not that's true or how often it needs to be done.

    Depending on where the problem is, you might need to order a part, you might need to scour the internet for it due to your fork's age, or you might be able to get something at a hardware store. Kind of depends on whether it's an oil or an air leak, and how lucky you are.
    I assume it's a bigger pain if it's an air leak because the seals are for oil only, no?

  4. #4
    Fat-tired Roadie
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    I don't know if this is true of the '01 model... SRAM only has a service guide for 2006 on their web site, and there may have been a design change between when Rock Shox made your fork and when that manual was published.

    However, it looks like the SID uses air pressure in the fork leg between the top cap and a piston with an O-ring. An air leak could come through the top cap, the valve, or around the O-ring. In 2006, and in my air fork (which isn't even the same company, so YMMV) there had to be a few ml of oil sitting on top of the air piston for the seal to work well and the fork to travel smoothly. Depending on whether or not that O-ring is damaged and if or when RS changed the design, it may or may not be a part you can replace. I wouldn't trust a 9-year-old O-ring to work if the person you're buying from actually rode much.

    When you get the bike, try airing it up and see if it works. If it won't maintain air pressure, take the top caps off and see if there's any oil in the air chambers (may only be an air chamber on one side, may be both.) If it's an oil leak, which is a little less likely, it could be a symptom of an air leak, or it could just mean you need a new seal wherever it's coming out. A few psi/month of air pressure loss is normal, but more than that is likely a problem.

    If it doesn't look like you can get the parts to do your own rebuild, consider a new fork. A professional rebuild can be an expensive service, and suspension forks have come a long way and do wear out over time.

    Some petroleum-based greases and oils attack some kinds of rubber. If in doubt, get fully-synthetic stuff.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

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