Classic & Vintage - Shimano XT M700 SP Rear Der

So I have one of these things on my main bike, an 85 Trek 520. It's getting to be pretty whimsical, in the sense that it doesn't feel the need to stay in the gear I want it to stay in. I've tried two methods of degreasing; a pressure spray degreaser and also soaking overnight in water with dish soap. I've reoiled with tri flow, but things seem to be getting worse. The 'super plate' seems to be quite gross inside, but i've been unwilling to try taking it apart for fear that i wont be able to put it back together again. I am sentimentally attached to this device, and it looks way cooler on my bike than some modern thing would, so..
- are these things fixable?
- is there an exploded diagram somewhere?
- anybody have any advice on how to go about cleaning this thing super thoroughly and trying to restore it to 'like new' quality?
- does the fact that i can't find any examples of other people who've done the same thing and written about it online mean that i'm a hopeless nerd?

btw, it shifted very well before it stopped shifting very well.

If you are talking about this dearhead, http://velobase.com/ViewComponent.aspx?ID=02f91c5b-c4bc-4a13-b17e-de448780c7a2&Enum=108, it’s no wonder you are attached to it. My suspicion is that the spring is giving out, especially if it has seen many years of work gunked-up. Many good bike shops have a hot-pot degreaser thingy that rattle parts around in a hot bath of degreaser, and can degrease anything. I know REI has them, and are little used. I bet they would love to fire one up and probably de-gunk your RD for free.:thumb:

-First, I would check your shift levers. Make sure there is enough friction in the lever to keep it from slipping, sometimes the screws come a bit loose.

-Second, have a look and make sure that nothing is bent. Look at the rear derailleur hanger on your frame and even the derailleur itself.

-Third, check the chain.

If slipping is the problem, I doubt that cleaning or excess lubricants are going to solve that.

Take it as far apart as you can and soak it in solvent overnight. My new favorite solvent lately has been charcoal lighter fluid, works GREAT and is cheap as back-alley sin. Works fast, aluminum friendly.

I'd check the shift lever friction too.
There should be a "D" ring to snug them up.

I just recently went to index shifting on my 86 Rock Hopper to match my other bike.
I was almost teary eyed putting "Mr. Antlers" to rest.

+1, check everything else before tackling the rear derailleur (i.e. work your way back from the shifters). In addition to the previous suggestions you should check the freewheel (bent teeth, loose cogs excessive play in the body), bent axle (causes cogs to run out-of-true), cables (rusting, excessive drag) and cracked frames (resulting excessive flex causes ghost shifting).

i switched the der with an extra i had sitting around and it shifts fine now. one of the pivots is pretty sticky, so ill try to clean it out if i can. i hope i can find something functional that is period correct if this thing is shot.

I am a dumby and took mine apart boohoo

Any advice getting it back together?

Bumping an old thread.

Can I mate these (first generation RD-M700) with indexed downtube shifters? Specifically some SL-6400s? I've about to switch to a 7-speed HG compatible freewheel, and thought I might be able to switch to indexed shifting as well.

I know, I know - try it and tell us. I don't own the SL-6400's, but might be able to pick some up for $20. Would prefer to pass (and keep my $20) if this is a fool's errand.

Cheers!

The Deore XT Superplate R. Derailleur (M700) is not index compatible, and trying to combine it with a set of indexed shifters will become an exercise in futility. If the Superplate is in good mechanical condition, I would remove it, clean it up nicely and find a nice display spot on your work shop wall. As the older posts may have elaborated on, a Superplate in good condition will command premium prices in the used market.

Alas, it is not a Superplate, but a first gen. M700 (link (http://velobase.com/ViewComponent.aspx?ID=2EDA0B89-6B14-4308-875B-21AD8F25CEED&Enum=108&AbsPos=244)). Speaking of which, I noticed that the inner (rear) cage plate is installed incorrectly in the photos on VeloBase - at least I believe so.

Thanks for saving me $20.

Cheers.

Alas, it is not a Superplate, but a first gen. M700 (link (http://velobase.com/ViewComponent.aspx?ID=2EDA0B89-6B14-4308-875B-21AD8F25CEED&Enum=108&AbsPos=244)). Speaking of which, I noticed that the inner (rear) cage plate is installed incorrectly in the photos on VeloBase - at least I believe so.

Thanks for saving me $20.
Cheers.



No worries! You are correct; the photo on VB shows the inner plate upside down.

What part of CO are you from?

What part of CO are you from?
Louisville