Results 1 to 22 of 22
  1. #1
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    28

    XT hub rebuild HELP!

    I'm trying to rebuild/repack mt rear XT hub (FH-M756). I took it apart, regreased bearings, re-assembled and when I put everything back together, it's very tight/sticky when I hand-tighten it. This is how it felt (but worse) before I started. When the lock-nut is just barely loose, it rotates smoothly, but with just a little bit of torque (hand torque), it becomes sticky and tight.

    Should I leave the lock nut (drive side) at the point where it rotates fairly smooth, but just hand-tightened? Again, with just the slightest amount of torque, it gets sticky/tight.

    Help a brutha out.

    PS- It's a bolt-on axle assembly.

  2. #2
    ...idios...
    Reputation: SteveUK's Avatar
    Join Date
    Apr 2006
    Posts
    5,662
    Too much grease? What kind are you using?
    When the axle rotates smoothly, is there any play in the assembly.
    Here's a link to my Shimano hub overhaul, in case you want a second opinion on what you've done!
    Last edited by SteveUK; 03-06-2007 at 11:02 AM.

    What use is a philosopher who doesn't hurt anybody's feelings? -
    Diogenes


  3. #3
    Trying a little
    Reputation: dusthuffer's Avatar
    Join Date
    Nov 2006
    Posts
    1,781
    don't leave the nut loose. tighten that up. I've never seen any torque spec published for that. But I hand tightend one once it worked loose on the next ride. Assuming you used green park grease, that's a bit too thick

    I never apologize. I'm sorry, but that's just the way I am.

  4. #4
    I Love my Rize
    Reputation: danoalb's Avatar
    Join Date
    Dec 2005
    Posts
    829

    Easy stuff

    Just make sure your bearings are seated properly (9 per side) and tighten it so it has the very slightest amout of play as when you tighten the skewers it will take the play out. One of the easiest ways to do this is to mount the wheel on the outside of the rear triangle one the non drive side of the frame with the skewer reversed. It will bind with only hand tightening. once you get it smooth tighten the locknuts and check for play. The play should disappear when you tighten the skewer. or check this out. If you have a bolt on axle just tighten it with no play but easy free spinning as there is no quick release to compress the axle.

    Quick-Release Hub adjustment
    Quick-release hubs are trickier to adjust, because the quick-release mechanism compresses the axle slightly when it is tightened. If you adjust the cones so that they feel just right off the bike, they will bind up when you tighten the quick release. You must set the cones so that there is a little bit of play when the hub is off the bike, or when the wheel is installed with the quick-release just barely tightened.
    Many people undertighten quick release skewers. You can sort of get away with this, because most newer bikes have vertical dropouts in the rear, so the wheel won't slip forward under load. In the front, we have the execrable "lawyer lips" to defeat the purpose of the quick release. This is still not a good idea, because the compression of the axle by the quick-release skewer helps protect the axle from breaking.

    To check your bearing adjustment, put the wheel into the bike with the quick release just barely tight enough to keep the wheel from falling out. If you are working on the rear wheel, take it out and re-install it so that the chain is not engaging the sprockets.

    Try to wiggle the rim back-and-forth between the brake shoes; since the QR isn't tight, there should be a bit of play. If there is, hold the tire so that the valve is at the 3:00 or 9:00 position, then let go of it. On most wheels, the valve is the heaviest part; on wheels that have spoke reflectors, the reflector will be the heaviest part. Whatever is the heaviest part of the wheel, it should cause the wheel to turn and swing back-and-forth like a pendulum, before finally coming to a stop.

    Once you have seen how the wheel turns with the quick release loose, try tightening the QR, then check again. If your bearing adjustment is correct, the play will disappear, but the wheel will turn as freely as it did when it was too loose. For very fine tuning of this, you can slightly vary the adjustment of the quick-release skewer, as long as it is good and snug.

    Some high-performance wheels have a seam filler in the rim that weighs almost as much as the valve, so you may have to clip a clothespin or spoke wrench onto the wheel to artificially make a heavy spot. This may also be needed on wheels that have hubs with rubber contact seals, like many newer mountain-bike hubs.
    Last edited by danoalb; 03-05-2007 at 07:23 PM.
    Early to bed early to RIZE makes a man healthy, wealthy <(scratch that) and wize.

    RIGHTY on a LEFTY

  5. #5
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    parktool.com has great repair instructions.

    But getting the proper final adjust for cup and cone hubs is a "feel" thing that can not be described. Take the hub to your LBS and ask them to show you how to do it.
    mtbtires.com
    The trouble with common sense is it is no longer common

  6. #6
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    28
    From SteveUK's step-by-step:

    ..."Keeping a finger on the drive-side end of the axle, flip the wheel and refit the non-drive side cone by screwing it down the axle until it just touches the bearings. Refit the rest of the assembly, turning the top nut to finger tight. All refitting adjustments from this point should be made from the non-drive side...."

    I follow the rest of the instructions, making all adjustments and tightening on the non-drive side and all feels perfect, BUT the top nut on the drive side is still just hand-tightened, and can be easily unscrewed. Should it be?

  7. #7
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by Author Unknown
    From SteveUK's step-by-step:

    ..."Keeping a finger on the drive-side end of the axle, flip the wheel and refit the non-drive side cone by screwing it down the axle until it just touches the bearings. Refit the rest of the assembly, turning the top nut to finger tight. All refitting adjustments from this point should be made from the non-drive side...."

    I follow the rest of the instructions, making all adjustments and tightening on the non-drive side and all feels perfect, BUT the top nut on the drive side is still just hand-tightened, and can be easily unscrewed. Should it be?
    NO!
    The Park Tools instructions: http://www.parktool.com/repair/readhowto.asp?id=105
    Then go see your LBS and ask for help.
    mtbtires.com
    The trouble with common sense is it is no longer common

  8. #8
    mtbr member
    Reputation: MRfire's Avatar
    Join Date
    Jan 2004
    Posts
    397
    Quote Originally Posted by Author Unknown
    From SteveUK's step-by-step:

    ..."Keeping a finger on the drive-side end of the axle, flip the wheel and refit the non-drive side cone by screwing it down the axle until it just touches the bearings. Refit the rest of the assembly, turning the top nut to finger tight. All refitting adjustments from this point should be made from the non-drive side...."

    I follow the rest of the instructions, making all adjustments and tightening on the non-drive side and all feels perfect, BUT the top nut on the drive side is still just hand-tightened, and can be easily unscrewed. Should it be?
    You have to hold the cone (make sure it doesn't move when at desired setting) with cone wrench and tighten the top nut against the cone (again, without moving the cone or it will screw up your setting). I just rebuilt the same exact hub with a new freehub and bearings.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    28
    "You have to hold the cone (make sure it doesn't move when at desired setting) with cone wrench and tighten the top nut against the cone (again, without moving the cone or it will screw up your setting)."

    Non-drive side cone, correct? I did that, but then I'm still able to unscrew the drive-side top nut with my fingers.

    A few more tries then it's off to LBS..

  10. #10
    mtbr member
    Reputation: MRfire's Avatar
    Join Date
    Jan 2004
    Posts
    397
    Quote Originally Posted by Author Unknown
    "You have to hold the cone (make sure it doesn't move when at desired setting) with cone wrench and tighten the top nut against the cone (again, without moving the cone or it will screw up your setting)."

    Non-drive side cone, correct? I did that, but then I'm still able to unscrew the drive-side top nut with my fingers.

    A few more tries then it's off to LBS..
    Both sides when settings are at desired level. Do drive side first....

  11. #11
    ...idios...
    Reputation: SteveUK's Avatar
    Join Date
    Apr 2006
    Posts
    5,662
    The instructions in my Shimano hub guide are correct....

    "Install the fresh bearings into the freehub, and drop the axle into place.
    Keeping a finger on the drive-side end of the axle, flip the wheel and refit the non-drive side cone by screwing it down the axle until it just touches the bearings. Refit the rest of the assembly, turning the top nut to finger tight. All refitting adjustments from this point should be made from the non-drive side.
    The idea behind cup and cone bearings is that the two races sandwich the bearings, but with the smallest amount of compression possible. Too much and the excess friction on the bearings/races will eventually cause them to disintegrate under load; not enough and the assembly will move around on itself, ultimately causing uneven wear on the bearings and races.
    So, once you’ve screwed the cone down to the bearings, back it off again by 2/3 minutes (60 minutes being one full rotation) and, holding the cone with the cone spanner, tighten the top nut..

    Like most things, it helps if you read it all...

    It goes on to say, "hold the axle at each end and wiggle it, then rotate the axle. Remember that you’ve just put fresh grease in the hub, so it’s not going to be super-smooth, but the axle should spin feely (try over-tightening slightly to get a feel for this). There should be no lateral play in the axle.
    Sometimes the tightening of the top nut will compress/relieve the assembly slightly, adjusting the adjustments you’ve made. If this happens, you’ll have to go back to square one and re-adjust the cone, taking into account the affects of the top nut. Loosen the nut; adjust the cone; tighten the nut; check; repeat until axle spins freely and without play…"


    The drive-side assembly should be completely fixed in place before re-fitting the axle into the hub. Once the axle is in and the non-drive assembly is rebuilt and all further adjustments should be made from the non-drive side. Tightening the top nut is part of the adjustment because the torque involved will compress the cones. If you get the bearings to run perfectly, the tighten the nut, you're going to have over-compressed the assembly. This is what seems to be the problem in the OP's case.
    Last edited by SteveUK; 03-06-2007 at 11:17 AM.

    What use is a philosopher who doesn't hurt anybody's feelings? -
    Diogenes


  12. #12
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    28
    I did read the whole thing (as I was working on hub), including the part where it says "all refitting adjustments from this point should be made from the non-drive side" which precedes "tighten the top nut."

    Being an unseasoned mechanic that's trying to learn something, I assumed that the top nut in which you were referring was on the non-drive side. No need to be rude.

    But thanks for the help nontheless.

  13. #13
    ...idios...
    Reputation: SteveUK's Avatar
    Join Date
    Apr 2006
    Posts
    5,662
    Author Unknown,

    Check my edit to my last post. I wasn't being rude, just trying to draw attention to yourself and Shiggy that you'd both missed something.

  14. #14
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    28
    No worries.

    Again, thanks for the help.

  15. #15
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by MRfire
    Both sides when settings are at desired level. Do drive side first....
    ummm...moving the cone on one side affects the bearings on both sides. You must firmly tighten one side first and make the adjustment from the other (with a few "tricks" to get it perfect).
    mtbtires.com
    The trouble with common sense is it is no longer common

  16. #16
    mtbr member
    Reputation: MRfire's Avatar
    Join Date
    Jan 2004
    Posts
    397
    Quote Originally Posted by shiggy
    ummm...moving the cone on one side affects the bearings on both sides. You must firmly tighten one side first and make the adjustment from the other (with a few "tricks" to get it perfect).
    Didn't I say do drive side first? I thought so. In the end, both must be tightened is what I was getting at...

  17. #17
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    28
    After some trials and errors, and with all the tips above, I now have a rear hub that is smooth as silk, with zero play, and locked up tight on both sides.

  18. #18
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    12,083
    So how many miles or rides until your next maintance???

  19. #19
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    28
    My entire stable is in a constant state of maintenance. I've just never re-packed a hub before.

    This particular wheelset is going on a frame that I haven't recieved yet. (Although, I do have a bike that I was able to give the hub a frame test with.) But once the new rig is built, I will check the hub regularly to make sure I didn't screw something up.

  20. #20
    Epic Photographer
    Reputation:
    Join Date
    Oct 2006
    Posts
    66
    Quote Originally Posted by Author Unknown
    I took it apart, regreased bearings, re-assembled and when I put everything back together, it's very tight/sticky when I hand-tighten it.
    Re-read the shimano page. Put in the NEW bearings. Bearings ovalize over time. You can't put the old ones back and expect they will all be in the right way (ie, the way they all became non-round). Buy new ones; they are cheap.

  21. #21
    mtbr member
    Reputation: MRfire's Avatar
    Join Date
    Jan 2004
    Posts
    397
    Quote Originally Posted by strathconaman
    Re-read the shimano page. Put in the NEW bearings. Bearings ovalize over time. You can't put the old ones back and expect they will all be in the right way (ie, the way they all became non-round). Buy new ones; they are cheap.
    +2

    These are the ones I bought:

    http://cgi.ebay.com/Campagnolo-Shima...QQcmdZViewItem

  22. #22
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    28
    Roger that. I just knabbed a bag of grade 25 @ 1/4 inch.

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

mtbr.com and the ConsumerReview Network are business units of Invenda Corporation

(C) Copyright 1996-2018. All Rights Reserved.