Shimano 105 r700 rear derailleur tension spring

seanoconn
seanoconn Posts: 11,739
in Workshop
Cleaning the bike today, not overly vigorously I thought. When I went to put the rear wheel back in there was a large amount chain sag. After much head scratching it seems the pulley arm which was working perfectly before is now stiff and doesn’t seem to be under any tension, so I imagine I’ve dislodged the pulley arm tension spring somehow.

Will I have to take the pulley arm off to get the spring back in place? Is there an easier method?

Or might there be another reason the arm is stiff?
Pinno, מלך אידיוט וחרא מכונאי

Comments

  • webboo
    webboo Posts: 6,087
    edited December 2022
    Is the free hub running smoothly. My chain was doing what you describe and I thought the spring had jammed but it was the hub.
  • seanoconn
    seanoconn Posts: 11,739
    Yep deffo the pulley arm. Should spring forward and back giving tension to the chain but but stiff and stays where you push it.

    I must have dislodged the spring by moving the pulley arm back to remove the rear wheel when I should have pulled the upper body of the derailleur. 🤷‍♂️
    Pinno, מלך אידיוט וחרא מכונאי
  • First.Aspect
    First.Aspect Posts: 17,379
    Why would moving it dislodge the spring?

    Anyway, they can get gunky in there, but easy to take apart and clear out. Might not be the same series, but the basic design won't have changed....

    https://images.app.goo.gl/wbVwJyWmZaZ56yDh7
  • seanoconn
    seanoconn Posts: 11,739
    It was fine before I cleaned my bike removed rear wheel 😕

    Removal, clean, make sure spring is in the right place looks like the fix. PITA
    Pinno, מלך אידיוט וחרא מכונאי
  • trevor.hall12
    trevor.hall12 Posts: 496
    Could be the spring broken or dislodged .
    Fir 20 quid you get new springs and bolts they are called plate assembly's, if you're taking it apart might be worth doing anyway as I would worry it will happen again if its dislodged

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