How to service the bearing on the drive side (XT rear hub)?

kilou
kilou Posts: 26
edited December 2014 in MTB workshop & tech
Hi,

I have a Shimano XT FH-M785 rear hub on my bike. When I did service it last year I removed the dust seal on the freewheel (drive side) in order to remove the ball bearing and clean it. This year when again servicing the hub I notived that the cone on the freewheel side was pitted. After looking around about this problem, I read that it is actually not a good thing to remove the dust seal on the freewheel as it gets easily damaged. It's well possible that this is what happened on my hub. Anyway I ended up buying a new hub as getting the axle and the cone was almost the same price. So I'm going to just replace the freewheel and keep the new hub as a spare. So for this time it's going to be okay but next time I'll service the hub, how should I proceed to clean the ball bearing on the freewheel side ? I don't see how I can take it off the freewheel without removing that dust seal... Is only the bearing on the non drive side serviceable on the XT FH M785 hub ??

Thanks for your input !

Comments

  • The Rookie
    The Rookie Posts: 27,812
    It's a freehub, not a freewheel by the way.

    Not taken apart an XT hub but a Deore, had no issue removing the seal and refitting it, were you reading up about the XT hub or cartridge bearing hubs which are a whole different ball game.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • kilou
    kilou Posts: 26
    Thanks for having corrected the wording: yes it's a freehub. Yes I've been reading the warning for the XT hub and it's also mentioned on the Shimano service file for the FH-M785 hub not to disassemble the freehub dust seal:

    http://cycle.shimano-eu.com/media/techd ... 750036.pdf

    Seen also (see point 5) but this is a more general piece of info:

    http://autobus.cyclingnews.com/tech/fix ... ix_freehub

    I keep on reading this warning but see no instruction on how to clean the ball bearing without removing that dust seal.
  • The Rookie
    The Rookie Posts: 27,812
    There is no need to remove the dust seal from the cone, it comes out with it, the rubber seal in the freehub, yes and with care.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • kilou
    kilou Posts: 26
    I may have found the culprit: the bearings were switched on my hub. I had the cage bearing on the right side (freehub) and the free ball bearing on the left side (disk) whereas according to this document it should be the other way around:

    https://www.paul-lange.de/tradepro/shop ... 5-3174.pdf

    If the free ball bearing is in the freehub, then there is no need to remove the rubber seal in the freehub to get it out since the balls can come out individually. I'll check when I receive the new hub if the bearings are mounted correctly.

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