Viewing 8 posts - 1 through 8 (of 8 total)
  • XT M8000 rear mech – lost tension. Repair or warranty?
  • simons_nicolai-uk
    Free Member

    My M8000 rear mech isn’t taking up chain tension in the higher gears – the cage has basically stopped rotating back more than about 90 degrees to the ground.  Under 2 years old so in theory in warranty.

    Are modern Shimano mechs servicable in any way?  The Park Tools blog https://www.parktool.com/blog/repair-help/rear-derailleur-overhaul is looking at a much older generation mech.

    Clutch has been squeaking for a while, it’s used with an oval chainring (in case either of those are relevant).

    mudhead84
    Free Member

    Turn the clutch off to see if it makes a difference. If it does, take the clutch cover off (three hex bolts on the front), give it a clean and tension it correctly to see if that helps.

    andreasrhoen
    Free Member

    @mudhead84:

    yes. This clutch thing needs service every 1/2 year or so. I use pm600 to grease it.

    oval chainring: re-grease the clutch even more often?

    Cover thing: when having the cover off and turning the clutch off the tension adjust mechanism stuff falls off with my Shimano rear mech. This stuff needs the cover to stay “in place”. I keep the clutch on when the cover is off.

    And: small adjustments on the clutch tension adjustment screw has huge effects

    Fresh Goods Friday 696: The Middling Edition

    Fresh Goods Friday 696: The Middlin...
    Latest Singletrack Videos
    simons_nicolai-uk
    Free Member

    Clutch on or off made no difference.  took the cover off trailside and loosened tension – doesn’t seem to be that causing the issue.

    Incidentally, no need to take the cover off to adjust – theres a little port covered by a rubber grommet.

    bigyan
    Free Member

    I would partially strip it and see if its the clutch (strip/clean/grease often fixes), if its squeaking it needs some maintenance.

    Exploded parts diagram

    http://si.shimano.com/pdfs/ev/EV-RD-M8000-3859A.pdf

    Service instructions

    http://si.shimano.com/#/en/DM/RD0004

    tomaso
    Free Member

    Mine had corroded and needed a bit of wire wool treatment and greasing before it would move properly.

    singlespeedstu
    Full Member

    Take the cage off and you’ll find that the bush behind the clutch is very dry/full of shit.

    Clean it all up then grease and re assemble.

    Was it squeeking when the suspension compressed?

    That’s a sure sign the bush is dry.

    singlespeedstu
    Full Member

    Take the cage off and you’ll find that the bush behind the clutch is very dry/full of shit.

    Clean it all up then grease and re assemble.

    Was it squeeking when the suspension compressed?

    That’s a sure sign the bush is dry.

    Good vid here on removing the cage.

Viewing 8 posts - 1 through 8 (of 8 total)

The topic ‘XT M8000 rear mech – lost tension. Repair or warranty?’ is closed to new replies.