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Dismantling a Shimano Freehub Body?

baccaman21baccaman21 Posts: 523
edited February 2008 in MTB workshop & tech
...is it possible to break one apart? (I'm talking Deore/LX 8/9spd etc)

I'm wanting to recondition a spare one that's gone sticky.

Whilst looking into the axle load bearing cup end I can see a couple of lugs opposite one another on the upper side of the race, I was thinking that a special pin spanner type tool could get in there and be used to unscrew this from the main body, thus revealing the inner workings?

Thing is, if this is the case, then what tool and where from?

I see park tools have this but that specifically states not for freehubs - which suggest there may be such a tool.

Obviously you can prize open the seal on the backface and access the inner bearings but that's as far as you can go... I think...

Any help or constructive suggestions appreciated.

P.S. I know I can 'just' buy a new freehub body, which is what I've done in the past, but I want to go deeper... (so to speak)

Cheers
get on your bikes and ride!

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    don't bother just buy a spare if you want one.

    even if you do get separated you wont put it back together again. there are two rows of loose balls (uncaged bearings).
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • cheers nick...

    not what I wanted to hear but thnxall the same... so much for recycling!?
    get on your bikes and ride!
  • nicklousenicklouse Posts: 81,520 Lives Here
    here is the info from Sheldon
    Servicing Freewheels

    Note: I advise against doing this, because it is generally not worth the trouble. The freewheel is the least important bearing on a bicycle, since it only turns when it is not carrying any load.

    Nevertheless, some people will ignore my advice and try to service freewheels, so here's how to do it:

    Screw the freewheel onto a wheel so that you will have something to hold it with.

    You should see a ring with two holes in it for a pin spanner to fit into. This is usually the ring which has the brand name of the freewheel marked, and may also have an arrow pointing clockwise, and the word "remove" in one language or another.

    If you don't see such a ring, you may need to remove the smallest sprocket to gain access to it. This is common on freewheels with 13 tooth or smaller sprockets. You will need two chain whips, one to unscrew the smallest sprocket, another hold the freewheel so that it doesn't spin backward while you unscrew the top sprocket.

    Use a hammer and punch (or an old flat-blade screwdriver) to drive the ring in a clockwise direction. This ring is actually a bearing cone with a left ("reverse") thread, and once you have removed it you will see a row of 1/8" bearing balls and a stack of very thin washers surrounding the threads that the cone threaded on to. These are shim washers, and you can remove one or more of them to make the bearing tighter, if the freewheel has too much play.

    If you want to disassemble it further, just lift off the cluster at this point and the innards will be revealed to you, including another row of 1/8" balls at the base of the freewheel, and two or three spring-loaded pawls which make the ratchet work.

    For re-assembly, you can use thickish grease to stick the balls in place while you reassemble the unit, but the tricky part is the pawls. In days of yore, there were special bobby-pin-like clips to hold the pawls compressed against their springs while you re-assembled the freewheel. These are no longer available.

    Instead of the special clips, you can use a rubber band with a piece of thread looped though it. Assemble the pawls to the freewheel core, then wrap the rubber band around them to hold them against their springs.

    Once the outer part of the freewheel is more-or-less in place, use the thread to pull the rubber band out through the middle of the freewheel.

    http://sheldonbrown.com/freewheels.html
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Amen.

    Point taken.
    get on your bikes and ride!
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