Any tips on cracked gears?


catnippertom

catnippertom

That Oregon Guy
1000004466.jpg

I have these two sets of drive wheels that have gears attached to them. They are both from different locos(bachmann and lifelike) that have the same issue. They end up just spinning when the motor moves them making the wheels not move. I bet this is a common issue but I'm just curious to how others have dealt with this issue. So far my idea regarding super-gluing the shit out of them hasn't prevailed yet. Any tips or am I just screwed?
 
Very common issue indeed, particularly with LifeLike Proto 2000 locos and to a lesser extent some Athearn and Walthers too.

I don't know about the Bachmann ones, but the LifeLike/Proto gears can usually be replaced either by complete replacement wheelsets (available from Walthers) which does give you a pair of surplus wheels, alternatively some of us use Athearn replacement gears pack reference number 60024 and replace just the plastic gear itself.

This latter option, you may need to gently drill out a little plastic from the hole to make them fit.

I wrote a guide to replacing cracked gears on another forum a while back, this link should work:
www.rmweb.co.uk

Proto 2000 GP Series Loco Cracked Gear Replacement Guide

Proto 2000 GP Series Loco Cracked Gear Replacement Guide Following on from some feedback in one of my workbench threads, I have written this guide for those who have Proto 2000 GP series locos with cracked gear problems. This is a common problem and affects Proto 2000 GP models of pretty much eve...
www.rmweb.co.uk www.rmweb.co.uk
 
As @jmupton2000 has posted, replacement gears are available from Athearn and Bachmann also have replacements for only a few $, although you do have to be careful fitting the new gears.
 
There are many posts on many forums addressing cracked gears, the whys, hows, and wherefores. Many cracked gears can be replaced, none can be repaired, and some are "throw away" when you find the cracked gears, since there is no fix for them.
 
That's just the nature of the design. When you press a plastic part onto a steel shaft and that is the only thing that gives it traction, eventually it will crack.
 
You might be wasting your time and depending on clearance with fit, you could take a black zip tie around the O.D. of the gear teeth.
Cinch it down without crushing the gear itself.
Next step is to mix up some J.B. Weld and apply with brush/Q-tip on O.D. of gear body.
I'd go the full circumference.
Maybe even put some down on the metal axle along the face of the gear body.
After everything dries, snip the zip tie off.
Before doing any of the above steps, I'd clean up the wheelset with rubbing alcohol.
Blue = zip tie
Orange and Purple= J.B. Weld application areas.
If it works and you get more road time, cool.
If not, well the loco goes to the work bench. :)
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I definitely would NOT recommend trying to repair the gears. LifeLike P2000 can definitely be replaced by the Athearn gears. They will probably fit on the axles without having to drill out the center of the new gears. You want some interference fit to keep the new gears from slipping on the axle. I would recommend you have a NMRA gage to be sure the wheels are the proper distance apart after reinstalling the one wheel. The problem originated because the Chinese-made gears were made of a type of plastic that shrank with time, cracking the gear. The Athearn gears are made with a different plastic.
 
Old 97 said:
You might be wasting your time and depending on clearance with fit, you could take a black zip tie around the O.D. of the gear teeth.
Cinch it down without crushing the gear itself.
Next step is to mix up some J.B. Weld and apply with brush/Q-tip on O.D. of gear body.
I'd go the full circumference.
Maybe even put some down on the metal axle along the face of the gear body.
After everything dries, snip the zip tie off.
Before doing any of the above steps, I'd clean up the wheelset with rubbing alcohol.
Blue = zip tie
Orange and Purple= J.B. Weld application areas.
If it works and you get more road time, cool.
If not, well the loco goes to the work bench. :)
View attachment 182874
Click to expand...
Have you tried this and had success?
 
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Okay, I didn't realize the second gear had a different crack.
So basically, I'd prep the gear with alcohol, place a zip tie on blue.
J.B. Weld green. When that dries, remove zip tie and J.B. Weld red.
When all of that dries, J.B. Weld yellow, both ends full circumference.
J.B. Weld is sandable, so you can take it down a bit if needed. :)
If none of this works, look at the ceiling, under your breath cuss "Old 97" and throw everything in the scrap yard.
Make sure you have a bottle of Dirty Monkey banana peanut butter whiskey.
Self medicate.
If needed, repeat steps from ceiling to finish. 🤣 🤣 🤣 🤣 🤣
 
I have successfully fixed cracked Life-Like gears by taking some K&S aluminum tubing of the proper diameter, cutting some very short pieces off (making collars), and pressing them on both hubs on of the cracked gear. Effectively squeezing the crack out of the hubs and gear.

Not for the weak of heart, though. I need to enlarge the aluminum collars by forcing them on an awl and stretching them slightly, and/or doing just a little filing on the hubs (chamfer the hub ends a tiny amount and even on the diameter a little bit) in order to get the collars pressed on to the hubs.

One could probably also use brass tubing, but the aluminum tubing is a tad softer and slightly easier to stretch (open up) with an awl. Once the collars are on, simply press the wheel axles back into the gears (ream out the gears if too tight, see further below), check and set the wheel gauge to the proper standard, then put the complete wheel assemblies back into the plastic truck frames.

After dropping the wheel assemblies in the plastic truck frames, check to make sure the collars clear the openings and don't rub on anything. In my experience, most of the time the collars cleared, but I ran into one truck one time that needed a slight shaving with an Exacto knife to create some clearance so the collars wouldn't rub on the truck frame.

In most of my cases, after reassembly, the loco will run just as quiet as before. In a few cases, I have noticed an almost imperceptible "click" as the loco runs, but nowhere near the very audible clicking and/or chattering noises and slipping like you get with a normal broken gear. In all cases, the locos ran nice and smooth, imperceptible click or not.

And, if you don't want to go through all this horse-pucky, I don't blame you. It's still far easier just to get some new Athearn gears for a quick, easy replacement. I had to invent the collar fix because I couldn't find any new gears in stock anywhere when I needed some. During the Covid shortages, go figure. I finally got a hold of some Athearn gears and have been able to use them instead. One thing I have done however, is to ream out the gear bores by hand slightly bigger, so they're not such a blasted tight fit on the axle shafts. This could possibly contribute to future cracking of the new gears. I use a #42 drill bit for reaming, it opens up the bore slightly yet still yields a nice, tight fit. A regular 7/64" diameter drill bit will also work as a reamer for those that do not have access to numbered drill bits. This will yield a slightly LESS tight fit than the #42 bit, but still tight enough to do the job, in my opinion.

This fix is for HO-scale Life-Like locos with cracked gears. I don't know if it will work for Bachmann or other brands or not, I haven't had any experience with cracked gears on any of them. Owners of those brands will have to judge for themselves if the hub collar idea is feasible for them or not.

Hope this helps. And if you care to try it, hopefully you will have some success, too. Like I say it worked good for me. :)👍

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Here's a set of 4 cracked gears (strung on a twisty-tie for safe keeping) that have been fixed with aluminum collars, all ready to go on the next Life-Like HO-scale 4-axle diesel needing some replacement gears. A friend's Highway Miniatures Erie B-2 Steam Crane that I built for him is graciously holding them up for the photo. 😁
 
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migalyto said:
I don't know if they what you need for these particular models, but this place has gears and parts to repair some of these locomotives with cracked gear problems.

Might be worth a quick email to find.

NorthWest Short Line

NorthWest Short Line
nwsl.com nwsl.com
Click to expand...

Huh, I could have sworn NWSL was going out of business a couple years ago. Looks like they were saved after all.

Assuming the product line is the same, their variety of wheel and axle sizes was always great for fine-tuning repairs.
 
catnippertom said:
Wow, I had no idea this was such a huge topic 😅 Thanks for all of the tips on this! I should be able to find something in here that works for me!
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Oh yeah, there was a problem some years ago where certain locos even had broken gears straight out of the box due to initial faulty manufacturing of the gears, so owners had to get creative for fixes, as you can tell from the above posts.
 
I was just working on an Athearn SD60 that is less than 15 years old and 4 of the 6 gears were cracked. I replaced them all with Athearn replacements. It still runs like an old Athearn though.
 
Pretty much every Proto 2000 GP I have ever bought here in the UK has had cracked gears, either on arrival or not long after. It does mean that you can pick them up very cheaply over here though which for someone who likes to kitbash, detail and repaint is a bonus.
 
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