Retrobike Forum Index

It is currently Wed Dec 12, 2018 12:19 pm

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 7 posts ] 
Author Message
PostPosted: Sun Oct 07, 2018 10:17 am 
Newbie

Joined: Sun Oct 07, 2018 9:46 am
Posts: 3
Hey guys, longetime reader, first-time poster here.
I recently acquired a steel Giant Boulder (from around 2000) with a rigid fork, meant to be converted to a cheap winter commuter. It is in pretty decent shape, except for the fact it's a bit rusty. It needed a good clean, tune and some new cables.

Alas, I now come to the conclusion that the spring in the pivot of the rear derailleur, which rotates the cage and tensions the chain, is seized/stuck/not working. It's a Shimano XT RD-M735, so a rather classic derailleur, even considering the decade the bike was built in. Problem is there is no way (I see of) to take it apart to replace or pre-load the spring.

I added a file to clairfy what part I'm talking about. It's the spring in the red circle that doesn't do it's job. I removed the screw that stops the derailleur from unwinding (at least, that is what is should do). Also, I removed a screw (blue circle) that keeps in place a "lip" or tab. I managed to rotate the tab (it's the one in the green circle). The cage I can turn a little bit back and forth, but that's it. There is no "modern" P-screw in sight. Almost bruised my fingers in trying to pull it apart. There is no apparent way for it to release the cage.

There is little information to be found on this specific model. This link http://www.disraeligears.co.uk/Site/Shi ... ge_51.html has an image of the original catalogue. It says that it's a "sealed pivot". Now I'm puzzled: was this derailleur never meant to be taken apart? It would be a shame to just throw out a classic part like this. And now I'm almost tempted to put my angle grinder to work just to see if there is a way to release the cage.

Anyone got ideas?


Attachments:
IMG_20181006_133636RM.jpg
IMG_20181006_133636RM.jpg [ 76.8 KiB | Viewed 629 times ]
IMG_20181006_133625_RM2.jpg
IMG_20181006_133625_RM2.jpg [ 109.49 KiB | Viewed 629 times ]
Top
 Profile  
 
 Post subject: Re:
PostPosted: Sun Oct 07, 2018 10:54 am 
Dirt Disciple
User avatar

Joined: Sun Jun 25, 2017 4:08 pm
Posts: 74
Location: witney
hi, had a smilar Deore lx m550 apart couple of weeks ago. it looks like the pivot/cage just needs a bit of persuasion . you have undone the tab screw,the tab is press fitted to the pivot which is press fitted to the cage i would say the pivot is corroded in to the derailleur knuckle and will require pulling or tapping free. maybe try supporting it in/over a vice and carefully tapping it with a punch or try levering between the cage and mech body with a large flat screwdriver.
good luck :)


Top
 Profile  
 
 Post subject: Re:
PostPosted: Sun Oct 07, 2018 8:47 pm 
retrobike rider
retrobike rider
User avatar

Joined: Fri Aug 08, 2008 2:36 pm
Posts: 17837
Location: Yorkshire, England
It's seized in, good luck getting it smooth, might need some work. It a good feeling when it works.

Prise it apart.

http://pedaldamnit.blogspot.com/2008/07 ... l.html?m=1


Top
 Profile  
 
PostPosted: Tue Oct 09, 2018 8:32 pm 
Newbie

Joined: Sun Oct 07, 2018 9:46 am
Posts: 3
Thanks guys, will try ye old vice. I doubt that it will release unscathed, but the derailleur is already useless in this state, so no harm done if it fails.


Top
 Profile  
 
PostPosted: Wed Oct 10, 2018 5:19 pm 
Retro Guru

Joined: Thu Aug 27, 2015 7:26 pm
Posts: 398
Location: French Alps
If it's rusted, electrolytic cleaning is the best way to go, as it doesn't remove any of the good metal, only reconverting the bad stuff.


Top
 Profile  
 
 Post subject: Re:
PostPosted: Fri Oct 19, 2018 9:10 pm 
Newbie

Joined: Sun Oct 07, 2018 9:46 am
Posts: 3
Thanks guys, with a lot of effort and tools I finally managed to pry it loose… but alas, the aluminum body is now cracked… It feels like a bit of a waste, but the amount of rust that came of out the body was insane; it was like someones literally drowned this bike. Replaced it with a modern derailleur so the bike now is usable again. Thanks again!


Attachments:
IMG_20181019_213835.jpg
IMG_20181019_213835.jpg [ 89 KiB | Viewed 362 times ]
IMG_20181019_213807.jpg
IMG_20181019_213807.jpg [ 87.67 KiB | Viewed 362 times ]
Top
 Profile  
 
PostPosted: Fri Oct 26, 2018 3:00 pm 
retrobike rider
retrobike rider
User avatar

Joined: Fri Aug 08, 2008 2:36 pm
Posts: 17837
Location: Yorkshire, England
or lots of spare parts


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: foz, Google Adsense [Bot], heymarge and 8 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

About Us

Follow Retrobike

Other cool stuff

All content © 2005-2015 Retrobike unless otherwise stated.
Cookies Policy.
bikedeals - the best bike deals in one place
FatCOGS - Fat Chance Owner's Group

Powered by phpBB® Forum Software © phpBB Group