Jockey Pulleys

[schrockbike]

I foolishly did not remove and clean my jockey pulleys (Acera derailleur) one at a time, and see that one has a metal sleeve inside the ring, and one does not. Both bushings seem to be the same length. The metal-sleeved one is slightly thinner. From my reading, it seems that this one is the "top" one (closest to the freewheel/cassette) that because it is thinner, it "wobbles" to make shifting easier. Do I have it right that I put the thinner one on top?

[DaveM]

Yes, the top pulley should be able to move side to side a tiny bit to help the pulley align under the cogs.

[bobtravers]

Usually, there's a "Centeron" marking on it...

[nfmisso]

Have you got the relevant documents from Shimano's TechDocs site?