HO bachmann locomotive

[DCrail]

I have a few vintage HO Bachmann EMD F9 diesel locomotives. A common problem is the gears in the motor/truck assy. break! These are plastic 8t/18t gears mounted on a steel shaft. There are 2 in the unit. Can anybody help me out?

[Trainman203]

We've said this before.  In today's model railroad world of limited parts availability and progressive introduction of improved versions of models, a new engine is often the best course.

[VTBob]

If you can find someone with a 3d printer, sometimes you can make your own gears. I'm in the process of milling my own driveshafts for the Climax gearbox. They don't make/don't have the old parts anymore.

Rob

[Trainman203]

Boy.  Let's build a space shuttle while we're at it.  If it was me I'd buy a new engine.  I have too much other work to do.

[WoundedBear]

Seeing as how Loctite 271 is a threadlocker (I use it frequently on my dragster), I fail to see how it can adhere the plastic gear to anything.

Where does all this wisdom you post come from?

I would think a strong cyano-acrylate with an activator would be the route to go.

Also.....I don't see the issue of plastic deformation being addressed. What do you do when the pitch of the teeth ends up being disturbed?

Sid

[WoundedBear]

20 units had there tear down inspections performed on the truck gearboxes.

The grammatical errors don't help to add any credibility to all this. 

Sid

[Trainman203]

I thought they were done their.  😂😂

[Len]

Sid - While sold as a thread lock, Loctite will set up in other situations where there is pressure contact between the pieces, like when a screw gets torqued, and air can't get at the bond while it sets.

I've used Loctite 271 to keep split pins, like these:

From moving around.

I've also used it with good results on a couple of diesels from another mfg that had wheels that kept getting out of gauge, even though the axle wasn't split.

Len

[WoundedBear]

I agree Len, but those pins are metal. 271 works fine on metal to metal joints, but has absolutely zero adhesion to plastics. That's where my confusion is coming from. And those engineering plastics that gears tend to get made from, should be even harder for 271 to grip to.

Sid

[Len]

That's what I thought too the first time I heard about using it to secure split axles in plastic gears. But for whatever reason, it works. Magic I guess.

Len