Late 40s / Early 50s René Herse tip find

[Jonny69]

Had a chance to take the derailleur apart to assess the damage (wear) and look at what I can do to save it.

It's taken a bit of head scratching to work out how it comes apart, but it felt like access to the pivot point was going to happen by taking the toothed jockey wheel apart. Some of these pictures are for my reference so I don't forget how to put it back together, by the way. This is one of them:



You can see the wear in the pivot in the pic below. My concern was basically that the derailleur would probably work just fine like this, but I have no idea how worn it is. If it's about to break through and it does break through, it'll get destroyed and won't be repairable. If I deal with it now, I can probably do something about it.



It looked like if I took the top race off the jockey wheel it might just slide apart and give me access:



None of my pin wrenches were small enough so I needed to make a tool. Aaaah! A scary piece of scrap!





Stuck the shaft in the vice with the soft jaws in, quick douse in WD40 and although it put up a small amount of a fight and bent my M2 'pins' it came free without damaging the holes:



Under there were 17 ball bearings which were ready to fall out all over the floor if I lifted the jockey wheel off, so I went and got some tweezers to tediously pick them out one by one:

 

[Jonny69]

There were some shims to set the tightness of the jockey wheel bearing, which I can use to nip it up when I put it back together. Then the lower race seemed to be what held everything together. With that removed I got my first view of the pivot:





Yeah. Not much meat left on there and I don't think that would have lasted long.



Because there's a long spring holding tension on this part all the time, it basically wears the back surface away. Looking at the image above, I think what I need to do is make a moon-shaped shim out of brass or aluminium and bond it into place. I have an aerospace structural adhesive I can use to bond the shim on permanently and it should be as good as new. An alternative might be to open the whole thing up a bit and and carefully file a ring to fit. I don't want to risk pressing something in because the metal is so thin on the back surface. The advantage of a full ring is although some of the original part has to be sacrificed, it does have a bit more surface area. Any other ideas welcome.

 

[rovarcycles]

Amazing find and restoration!

 

[dirttorpedo]

There were some shims to set the tightness of the jockey wheel bearing, which I can use to nip it up when I put it back together. Then the lower race seemed to be what held everything together. With that removed I got my first view of the pivot:

View attachment 872427

View attachment 872428

Yeah. Not much meat left on there and I don't think that would have lasted long.

View attachment 872429

Because there's a long spring holding tension on this part all the time, it basically wears the back surface away. Looking at the image above, I think what I need to do is make a moon-shaped shim out of brass or aluminium and bond it into place. I have an aerospace structural adhesive I can use to bond the shim on permanently and it should be as good as new. An alternative might be to open the whole thing up a bit and and carefully file a ring to fit. I don't want to risk pressing something in because the metal is so thin on the back surface. The advantage of a full ring is although some of the original part has to be sacrificed, it does have a bit more surface area. Any other ideas welcome.

The Red Green solution would be filling it with JB Weld!