Seized Ultegra RD-6700 rear derailleur pivot bolt

andyeb
andyeb Posts: 407
edited November 2015 in Workshop
I'm trying to strip down my Shimano Ultegra RD-6700 rear derailleur, as per this video:

<https://www.youtube.com/watch?v=L5KWFhzIPoc&gt;

...however this rear mech has a pivot bolt which attaches the cage, rather than a p-screw.

The problem is that the mech is "sticking" on picking up slack in the chain, which results in a visibly slack chain on small cog combinations. Unfortunately a simple lube and working the pivots does not appear to be solving the problem - the join is still "sticky" so clearly needs stripping down properly and re-greasing.

The problem is that the pivot bolt seems to be seized hard into the main derailleur body. Being a dad, I am well exercised in opening jam jars, but even with a decent length allen key, I just can't shift it.

Any suggestions for freeing this seized bolt?

So far I've tried squirting as much WD-40 as I can into the proximity, but the bit of the bolt which is really seized is deep inside the derailleur :(.

Any suggestions gratefully received.

thanks,

Andrew

Comments

  • Rightarmbad
    Rightarmbad Posts: 216
    Just sounds like your chain is too long or worn out or the B tension needs adjusting.
    Or you fitted a cluster outside of it's capacity.
  • andyeb
    andyeb Posts: 407
    OK I've managed to sort it. Turns out the cage pivot bolt is hollow and so if you squirt WD-40 down inside the bolt (where you put the allen key to loosen it) and leave it for a bit to penetrate the thread, it will eventually free with a lot of elbow grease.

    Turns out the cage pivot was in a really bad way and I'm honestly amazed that the rear derailleur was working as well as it was in this state; the cage pivot bearing and tensioning spring were covered in rusty brown gunk. It took me some time to separate the bolt from the bearing and when I did, the inside was also full of rusty brown gunk, as was the inside body of the derailleur which houses the bearing and retaining spring.

    Having given everything a really thorough clean with powerful degreaser, packed with fresh Shimano mutant gorilla snot grease (you know, the stuff which looks like it should glow in the dark?), reassembled, it's now working like new again.
    Rightarmbad wrote:
    Just sounds like your chain is too long or worn out or the B tension needs adjusting.
    Or you fitted a cluster outside of it's capacity.

    Although I've changed both the chain and cassette several times on this bike (it's done nearly 15K miles through all weathers), I've always replaced like-with-like, making sure I match the chain length each time, taking stretching into consideration.

    Looking at the state of the inside of the mech, I'd left it far too long and should have overhauled the mech before it started acting up. Generally I'm fairly hot on staying on top of bike maintenance, but sometimes a bit reluctant and under-confident learning and doing new stuff for fear of breaking or damaging things. But as I've seen, leaving components until they are seizing up before acting is perhaps more damaging, so I may as well cut my losses, watch a few YouTube videos, roll up my sleeves and dive in.

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