Tightening up a Deore Lx Rear Derailleur

[cmjc]

It's 1992, long cage, and still working perfectly well, but I feel the cage moves too much towards the wheel because of play at the pivot point where it attaches to the derailleur body.

I've never dismantled one, so I'm wondering how that pivot is made, and can I tighten it up a little to remove the play? Is it a bolt and nut, or press-fit, non-adjustable design?

If I can't tighten it up via the pivot bolt, I'll try making a plastic shim to insert between the cage and body.

Advice and suggestions please.

 

[jim-laden]

It's 1992, long cage, and still working perfectly well

If it aint broke n'all that!!!!!

Anyhoo if you fancy a fiddle the pivot bolt is held on by a circlip on the back.

Not had any experience with LX mechs per se but on my XT one there are 2 (I think) rubber O rings seals on the pivot bolt its self. Maybe they have perished?

In my honest opinion I'd leave well alone. There is always going to be some degree of play and as long as it's shifting fine you may be trying to solve problems that don't exist.

Have a cup of tea and a little think I say!!!!

Laters Jim

 

[cmjc]

Point taken Jim, but we all love to fiddle

Actually, when I got the bike from Tokyo a few months ago, and restored it, the first thing it needed was the hanger straightening, it was well bent. It is straight now, but the waggle in the RD is excessive, perhaps 5-10mm laterally.

I'll try making a plastic shim first, rather than dismantling the derailleur.

It'd be nice if somebody has a picture, or diagram, of how the cage pivot bolt is designed.

 

[jim-laden]

Re-read your post and I must have grasped the stick at the wrong end!!!!

I was talking about the main pivot (where it fixes to frame) not the part you are interested in!!

As far as I know, and I'm ready to be proved wrong, the pivot you are interested in cannot be dismantled as it's riveted not bolted.

You may have to get your fettling fix from some other component on your steed!!

Laters Jim

 

[rc300]

You can drop the arm off by undoing the small allen key pin. Pretty much the same setup at the mounting bolt o ring on a stub axle. Will post up a pick of dissasembly later today as I have to service a old xt one.

 

[cmjc]

It worked!

I employed one of those flat plastic date stamp tabs supermarkets use to seal loaves of bread.

Using scissors, I made the hole in it about 1cm in diameter. Then with a table knife, I eased back the black nylon collar around the junction of the cage and body, and between the collar and cage slotted in the plastic shim I'd made. It even made a satisfying "click" as it went in, indicating that its open ends had snugged around the pivot. The whole process took about 60 seconds from the bread-bin to the glow of success.

I discovered the pivot seems to have a spring on it under the circlip, so the 1mm thick shim has tensioned that spring enough to take out some slack. It still waggles, but noticeably less.
A squirt of oil, and a satisfactory 10km road test: Result = a very happy fiddler.

Now for that cuppa Green Tea!

 

[cmjc]

Will post up a pick of dissasembly later today as I have to service a old xt one.

Yes please, I'm curious what's inside, and your pictures will help future visitors here.

 

[rc300]

here ya go!

1 First remove the stop post from the arm and it will spin round.
2 Then at the back of the mech you will see a small phillips screw. Remove and then you will be able to remove the arm from the body
3 Make a note of where everything came from. Clean and inspect the spring which will come out the main body, and whatever else needs it! and replace the small o ring if it looks flat as this is causing a degree of play in the arm.
4 Re grease and replace spring and make sure you remembered which way it came out and also what hole it located on on the arm. Push the assembly together and replace the small screw which will hold everything together.

Hope it helps

 

[cmjc]

Thank you Sir!

That's a great help to me and others.

No circlip then, just screws and a spring. The "o"ring you mention is the one that lies flat around the base of the pivot... right?

I suspect that is worn in my case, that's why making a plastic shim has removed some of the play.

You circled a black line on the pivot bolt, it that wear, or an "o" ring?

I'm tempted to strip mine down and fix it properly as you have done.

I wonder how much sideways waggle is acceptable?

I'll test some new rear derailleurs in the shop...

 

[rc300]

the black line is the o ring on the post. and the black plastic shim arount the base can wear too and help to develop a little play but most comes from the shaft as it is held together by the tabbed washer and screw.