Choosing between a full gear rebuild or a drop-in unit on a 1980s Otis traction machine

About six months ago, I got called to a small apartment building downtown for a machine room noise complaint. The old traction drive was howling like a banshee. I had to pick between a full gear and bearing rebuild on site, which would take maybe three days with a helper, or ordering a whole new drop-in gear unit. The drop-in was faster, about eight hours once it arrived, but cost the building owner nearly double. I went with the full rebuild because I could see the main shaft was still in great shape, just the worm gear was shot. It was a long, greasy job, but getting that old machine quiet again felt like real craft. Now it runs smooth as butter. Anyone else faced that kind of call on an older traction unit? What made you pick one way over the other?

3 comments

3 Comments

parker_hall54d agoMost Upvoted

Had a 1985 Dover unit in a medical office last year with the same call. The worm gear teeth were just gone, like someone took a grinder to them. I mean, the drop-in was tempting for speed, but the housing was solid and I had the shop time. Took me and an apprentice two full days to scrape and fit the new gear set. The sound it makes now, just a quiet hum, is so much better than that new unit whine.

the_julia4d ago

What condition was the main bearing housing in when you opened it up? That's often the real deciding factor for me. If the housing is worn or scored, a drop-in unit saves a lot of future headaches, even at the higher cost. But if the housing is true, rebuilding around a good shaft is the right call. You just can't beat the smooth run of a properly fitted gear set.

skyler_johnson324d ago

Properly fitted gear set" sounds nice but man, that's a lot of work. Parker_hall5 talking about two full days, I'd just want the thing running. If the housing isn't totally trashed, a drop-in gets you back online way faster.