Cracked WBB worm gear - UPDATE

Curt, great job! If you don’t mind, share your remove & replace process please…….

Pat

@harmonyards posted:

Curt, great job! If you don’t mind, share your remove & replace process please…….

Pat

I was also wondering about getting the captured gear into the truck.  I'm assuming you block it up from the back and use a press, but that's just a guess.

Thanks Pat!

I’ll qualify this by stating I only wish I had the tools that you have on your workbench!

I used a small flathead screwdriver and hammer to tap the shaft from the compression collar (or nut, if you prefer) that holds everything in place. Once the collar was removed, I used the same tools to remove the shaft from the truck. The cracked gear easily came off while removing the shaft.  I next positioned the replacement worm gear in the slot in the truck and slid the shaft back into place and partially through the worm gear. I then placed two small flathead screwdrivers alongside the gear on the collar side of the shaft (to hold the gear in place) and using a hammer, tapped the shaft through the gear till it was properly positioned. I reapplied the compression collar using a large pair of pliers. It goes without saying that care must be taken to make sure the brass gear on the side of the truck properly meshes with the drive gears on the side of the truck. The compression collar must also allow some “play” in the shaft or the large drive gear may bind with the others.

If I had to do these frequently, I’d probably create a shim or backstop to hold the gear in place while I tapped the shaft through. The two screwdrivers worked but, it was awkward. I figure cutting enough from a large, thick flathead washer to allow it slip over the shaft should work as a backstop of sorts. This would then be removed once the worm gear is properly seated.

Curt

Curt, nice job. You’ll cherish that engine forever since you brought it back to life.

Thanks Curt, I wondered if there was something I was missing, but it sounds like what I expected.  The important part is, you got it on and it works.

@juniata guy posted:

Thanks Pat!

I’ll qualify this by stating I only wish I had the tools that you have on your workbench!

I used a small flathead screwdriver and hammer to tap the shaft from the compression collar (or nut, if you prefer) that holds everything in place. Once the collar was removed, I used the same tools to remove the shaft from the truck. The cracked gear easily came off while removing the shaft.  I next positioned the replacement worm gear in the slot in the truck and slid the shaft back into place and partially through the worm gear. I then placed two small flathead screwdrivers alongside the gear on the collar side of the shaft (to hold the gear in place) and using a hammer, tapped the shaft through the gear till it was properly positioned. I reapplied the compression collar using a large pair of pliers. It goes without saying that care must be taken to make sure the brass gear on the side of the truck properly meshes with the drive gears on the side of the truck. The compression collar must also allow some “play” in the shaft or the large drive gear may bind with the others.

If I had to do these frequently, I’d probably create a shim or backstop to hold the gear in place while I tapped the shaft through. The two screwdrivers worked but, it was awkward. I figure cutting enough from a large, thick flathead washer to allow it slip over the shaft should work as a backstop of sorts. This would then be removed once the worm gear is properly seated.

Curt

I’ve fixed several of these as well, and you nailed it, ….I’ve fashioned the back stop shim from a piece of milled aluminum that basically looks like a miniature tuning fork. I don’t use the press for these either. I prefer the sneak up on it tap, tap, tap approach too,….if I feel I tapped and hit solid I know to stop…..I’m skeptical on pressing these. They sure look like they can go sideways quickly if you’re not careful,…..nice job!!

Pat

Nice job, I'm not sure I would have pulled that off.  I was lucky to get a replacement truck from Bachmann.

This seems to be a relatively common problem with Williams worm gears, huh? https://ogrforum.com/...k-worm-gear-question

Sadly Frank Timko is no longer a source for replacement parts.

I’ve only had to replace a WBB motor truck on an engine once previous to the worm gear on my L&N FA-1 cracking. Having experienced only two cracked gears out of 30 two motor engines over the years, I probably wouldn’t characterize this as being a common problem.

Obviously simply replacing the entire motor truck would have been easier (and more expensive) had Bachmann any available but; the repair really wasn’t that difficult once I learned NWSL had the correct replacement gear. And honestly, as Rod alluded to in his post, it’s a nice feeling of accomplishment to repair something and bring it back to life. It’s just another aspect of the hobby.

Curt

The issue of cracked gears seems to be a "common" issue on specific models.  For instance, the Century Club TMCC PRR Shark A-A had that problem, I ran across it several times with repairs.  Then I bought the Century Club A-A Sharks at York a few years ago.  It had not one, but two cracked gears.  As it turned out, I could actually still buy the trucks from Lionel parts.  I also discovered a different power truck has the same gear, so I bought a couple of spares.

Some of the Early MTH PR E-8 had this issue, long ago I found MTH had that gear as a part.  Once assembling though I use a vice with spacer to press back on gear or wheel, with a center spacer that ensures one side of the vice is pressing on the axle of the wheel or gear you don't want to have move on the axle.  Vice gives nice precision movement, as I like to avoid impacts when reassembling something like this.  G

Good for you that you were able to get a replacement. I contacted NWSL last year about this same issue with a Weaver truck, that is basically identical to the Williams truck, and they told me they didn't have anything like that in stock and they never made anything like that.

@Mike D posted:

Good for you that you were able to get a replacement. I contacted NWSL last year about this same issue with a Weaver truck, that is basically identical to the Williams truck, and they told me they didn't have anything like that in stock and they never made anything like that.

It’s available right now on their website. In stock

Pat

@harmonyards posted:

It’s available right now on their website. In stock

Pat

I checked their web-site and after some research into gear pitches and such, I found a gear that looks closer to the one I need but it is a 48dp. How do I go about determining if this gear pitch will work with my worm?