Shimano 600 RD-6208...Spring Tension Issue.

[bikeworkshop]

I'd take the jockey assembly apart, and also the main spring assembly.
The rest i would dunk in the parts cleaner, because i don't know that further dismantling wouldnt do more harm than good.

 

[Tootyred]

They come to bits pretty easy. Most shimano rear mechs of that era are very similar to pull apart. Its worth doing as both the internal springs tend to get the grease washed out.

Normally there is a big circlip and once off the pin will pull out. BUT....when undone they will unwind the springs amd you need to know which way they came out and how to put them back.....tbh....you probably want a diagram.

Shimano have a technical back catalogue btw.

 

[Mr Weirdo]

I'd take the jockey assembly apart, and also the main spring assembly.
The rest i would dunk in the parts cleaner, because i don't know that further dismantling wouldnt do more harm than good.

Would you grease the main spring assembly before you put it back in? Thank you.

 

[Mr Weirdo]

They come to bits pretty easy. Most shimano rear mechs of that era are very similar to pull apart. Its worth doing as both the internal springs tend to get the grease washed out.

Normally there is a big circlip and once off the pin will pull out. BUT....when undone they will unwind the springs amd you need to know which way they came out and how to put them back.....tbh....you probably want a diagram.

Shimano have a technical back catalogue btw.

Thank you...Prior to removing the pin I liberally applied penetrating oil which has degreased the internal spring so I guess I need to regrease it. Is there a reason why my jockey wheels have a capital A on one and a capital B on the other? In hindsight I should of taken more notice when pulling it apart...lesson learnt hopefully!

 

[Tootyred]

Yes, grease it. The important bit is the shafts inside. These don't have a bearing, using a bush. The bush relies on grease to keep it free and stop early wear....nobody likes a dry bush!

 

[Tootyred]

take photos as you pull it to bits at each stage. Then you can use them to help reassemble.

 

[bikeworkshop]

Would you grease the main spring assembly before you put it back in? Thank you.

You want the internal parts to be lubed to prevent corrosion - a decent spray oil is commonly used as it gets everywhere. grease might last longer but also might collect grime.

Yes, grease it. The important bit is the shafts inside. These don't have a bearing, using a bush.

The frame-mounting bolt pivot assembly gets sticky over time - a good clean and grease and it'll do another 30 years.

The jockey cage pivot can often be freed up with light oil.

Is there a reason why my jockey wheels have a capital A on one and a capital B on the other?

A pulley and B pulley are the guide and tension pulleys - top pulley has a little side to side float to allow the chain to align perfectly with the rear sprocket.
The bushes the jockeys turn on are a different length to allow this.
Good luck - it's a fantastic piece of design

 

[Tootyred]

Guide pulley at top should have a bigger diameter metal cover and a ceramic/ ceramic bush.

 

[Tootyred]

https://si.shimano.com/en/manual/search?input_model=RD-6208
Heres a link. Orange button at bottom of list marked EV should open you a pdf of the mech.

 

[bikeworkshop]

I love the shimano diagrams