Re-attaching a pot-metal odometer gear to the shaft?

[Full Monte]

Well, I just took apart the odometer on the '87 300D. The odometer shaft has a plastic gear on one end and a pot-metal gear on the other end. When the odometer stops working, it's usually the pot-metal driven gear that is slipping on the shaft. I tried the Diesel Giant technique of using Loctite, but it didn't work. The gear still slips. But, instead of scraping up the shaft, I scraped up the inside of the hole on the gear. It looks like I better do both.
Any advice would be appreciated.

 

[The Warden]

I think you're on the right track with planning to scrape the shaft as well as the hole in the gear. The rougher you can get them, the better.

If Loc-Tite doesn't work after that, maybe try a small amount of epoxy?

 

[argve]

never having seen what you're working on but can you drill into the side of it and install a very small set screw and use loc-tite on it?

 

[Full Monte]

Thanks, guys. I was thinking along the same lines. I talked with a machinist friend of mine who happens to be coming for a visit. I'll talk with him about the set screw idea. He suggests drilling a hole part way through the shaft (7/64 dia.), and putting in a small ball bearing with loctite.
The ball will stick up above the surface. Then, he says to mill or file a slot in the pot metal to allow the shaft with ball to slide in. Assemble with loctite. Sounds like it would work, as long as we can drill a hole that small on a round shaft. He says he's done it several times. I better get out the magnification goggles...

 

[Full Monte]

We took the odometer apart again. It turned out that the shaft had seized due to some loctite getting between the shaft and the plastic bearing surface on the pot metal gear end of the shaft. The interesting thing is that you can reassemble the gear on the shaft, after scratching up the inside dia. of the
pot metal gear. You do this without removing any of the number gears. Putting a small drop of loctite on the inside of the pot metal gear, you slide and press it onto the shaft, hoping the loctite and scratches will keep the gear from slipping.
Unfortunately, you have to slip the shaft into its plastic bearing at the same time, immediately after it has come into contact with the loctite. While it seemed to move freely initially, it did seize up later, causing the plastic gear on the other end of the shaft to slip. I used a little WD40 on the shaft, while working the mechanism back and forth to free it up. It's working now.
Oh, and after removing the cluster from the car for about the fourth time,
it took me all of 4 minutes to remove the cluster from the car, 7 more minutes to get the odometer apart down to the gear train. Much better than the first time I did this ( a week of messing around and asking questions online).