joeswamp

So I've been riding my beloved 1972 Raleigh Pro on the rollers (rather than the road) and I haven't done a lot of shifting. This winter when I went to use it I discovered that the rear derailleur is really sticky -- it's really hard to pull on the shift lever and the spring can't move it to the smallest cog. This is a patent 72 Nuovo Record.


I take the derailleur apart and it's the parallelogram. Three of the pivots are fine (you can tell because you can easily slide the plates from side to side -- there's about 1/2 mm of play there), but one pivot is exhibiting a lot of friction. I cleaned the parallelogram in my cheapo ultrasonic cleaner (thinking maybe there was some dried grease in there), the parallelogram got really clean but it was then even harder to move back and forth. I then alternated saturating the pivots with triflow and moving the linkage back and forth a hundred times.


It's now about the same friction-wise as it was when it went into the ultrasonic cleaner. Right now the sticky pivot is soaking in Kroil as I have run out of ideas. Am I outta luck here? I know it's theoretically possible to replace those pivot pins but I think you need some special equipment (as well as replacement pins). Is there some magic method to freeing these up? I searched the forum and couldn't find anything.


Thanks for any help...

davester

I've had some luck with a similarly sticky NR by alternating solvent, ultrasonic, Kroil, and Triflow numerous times. However, it could be that your pin is bent in which case nothing will work.

merziac

We need pics, go say Hi and or comment to get to 10 posts so we can see what you got.

joeswamp

Thanks guys, I don't think the pin is bent because the derailleur has not been banged up at any point and it used to work.

Got an interesting suggestion on another forum: clean it again with Simple Green (which is aggressive on aluminum), rinse, dry with compressed air, and work it back and forth dry. His theory is: By lubricating it before working back and forth I'm not letting the oxides and crud wear off.

Think I might try that today. Will also try to get my post count up so I can post pics (and read PMs). I've been lurking on this forum for years but I've never posted anything because someone had always provided the info I was looking for!

smontanaro 

If worse comes to worst, all is not lost. NR rear derailleurs, while not a dime a dozen, are plentiful on eBay, and if you're a little patient, can be found in good condition for about 50 clams. Here's one for not much more than that: https://www.ebay.com/itm/254080095823 Sometimes, people sell just the parallelogram assemblies. Also, if you are determined to keep the same body and it does turn out that your pin is bent (seems unlikely, as you didn't report you had problems before putting your bike on the trainer), Jim Merz over on Classic Rendezvous can almost certainly replace your pins. That might cost as much as a good used derailleur.

joeswamp

Thanks, I guess these things are a little cheaper than I thought on eBay (I guess they made lots of them). I'm going to try a little harder to fix mine before I give up.

Thanks for mentioning Jim Merz -- just looked up his facebook page and he's doing some amazing machine work (like reproduction Chater-Lea components). Good guy to know about.

rootboy 

The bushings set into the aluminum pivot bodies are made of bronze. The pins may be made of aluminum, but in my minimal experience, it seemed like a slightly different
alloy to me. Maybe aluminum with higher content of something that made it more malleable than standard alloys, in order to facilitate the peening operation. Maybe not.
Campagnolo undoubtedly peened them on a big press. I did it by hand tool and even had some trouble with NOS Campy pins.

When I use to try to take these apart and refurbish them, I found that the pivots that were very stiff usually had worn pins in them. A groove formed in the pin from the bronze
bushings. Made it almost impossible to drive the pin out. Had to be drilled out.
Anyway, I suspect that the binding is being caused by wear in the parts. Either in the pivot knuckle, the bushing, or the pin, or maybe all three.

rootboy 

If I was going to try to fix this, as a last ditch effort, I would place the stripped down parallelogram into a soft jawed vise, and take a brass drift, like maybe a 1/4 or 3/8 inch chunk of round brass bar stock, and try to tap the pivot knuckle in various directions, to try to loosen up the connection.
But with the pin being seized into the knuckle and immovable, and the bushing being held firm in its place inside the front and rear plates, it may not do much good. But it could jar things enough to loosen up the binding parts. Good luck.

merziac

Yep, absolutely correct, good guy to know about.

repechage

Was not Chater-Lea brand trying to restart a while ago? This reminds me that after the announcement, nada.

As to the stiff parallelogram... I assume the spring was removed, were the limit screws as well, or backed out to provide as much as possible mechanism movement? I have done that and it helped. I do not like ultrasonic cleaners for cleaning "trapped" mechanisms.

joeswamp

Yes the whole thing was stripped down to the bare parallelogram. I cleaned the lubricant out and worked the mechanism back and forth dry (well at least the one bad pivot was dry), then worked the mechanism some more after soaking the pivot in Kroil. It's maybe a little better, but I think I'm going to need a lot more cycles. Now I'm wondering if I should flow some abrasive in there, on another forum someone suggested mixing some microabrasive with a liquid that creeps in (Kroil or acetone), flowing it into the pivot and then cycling it some more. It's an interesting idea but I worry I'd never be able to get it all out.

I did find a piece of brass and was able to drive the plate laterally between the yokes (there's about 1/2mm clearance there). I was hoping this would free it up but no such luck.

Guess it might be time for a new derailleur. This one did lead a good life...

merziac

Probably not a bad idea to get a replacement. In the meantime I would soak it in grease heated up with a hair dryer or heat gun to liquify, it might get in there and do the trick, Marvel Mystery oil or STP might also work.

Salamandrine 

At some point it was explained to me how to remove and replace pivots on a NR derailleur. I definitely remember people that knew how to do it, but don't remember what the procedure was. Taking a NR derailleur apart actually was something that was sometimes done, just not very often. Normally they would last near forever with minimal maintenance.

If it was mine, I'd give pivot replacement a try. Seems like a new pin could be made from 6061 round stock easily enough. Depends on your comfort with fabrication. It might be prudent to locate a replacement RD first.

repechage

might try a lock ease fluid.

73StellaSX76

I replaced the pivot pins on mine with brass sometime in the early 80s. But then I had access to a machine shop with a drawer full of reamers. Still, it's a pretty straightforward job even I could manage.