Old M739 XT derailleur

[lingus75]

I think it may be dead, but on the off chance can the spring (where the top jockey wheel joins the main body of the mech)which takes up the tension of the chain be 'de-clagged'? When on the middle ring and high gear it wont take up the chain slack so chain rubs on the chain stay. Its fine when on the big ring.

I tried to work some gt85 into the mech, but the spring doesn't seem to have enough spring to work properly anymore.

[Spydaman]

I haven't got one in front of me but pretty sure you can remove a circlip then dismantle the spring for de-clagging.

[Justin S]

I am sure that if you remove the cage and jockey wheels, there is a countersunk allen bolt , you can undo and remove the spring and clean the bushing. Remember to use Loctite on the bolt when refitting, as from experience they can undo and destroy the mech.

[ecsrobin]

Is that an 8spd mech?

[lingus75]

Yep, 8speed.

So, looks like I may be able to work on it which is great news! Any special tools needed? It's my daily steed, and don't want to be stuck with a mech in pieces at 9pm not having tools to refit.