I convert Bachmann HO scale GE 70-tonners to HOn3 per the Hauff brothers method in the July 2008 RMC. Lately I’ve had several cracked “cups” – the U-joint like pieces that the “dogbone” fits into on the motor and the gear that fits on top of the trucks.Then you go from being a very light B-B loco to a 0-B loco and can hardly pull yourself.
The B-mann in his infinite wisdom doesn’t list this as a separate part[:$][oops][:(!]
Look like you can buy them attached to more expensive parts that typically don’t fail. Or just buy a whole new loco to serve as parts queen?[banghead]
My guess is that one of the NWSL “Sahft Coupling Driveline Universals” will fit, but I don’t have any easy way of accurately measuring the connecting shafts. Anyone know what I need?
Now there’s an idea. I gave it a try and it does seem to help. Still having trouble at one end, which may be a bind further down in the gear train in that truck, but will have to get back to it later.
I’d still like to eventually just do it with correct-fit parts. Since I am building a small fleet of these, that’s a better solution in the long run – and probably less labor intensive.
Mike, I have had the same problem in the past, and fortunately, NWSL does makes the stuff you need. The part number of the kit that I used is 485-6. It includes a couple of different sizes of ball cups, so you may need more than one kit.
I’ve managed to get the driveline squared away. The truck gear train is binding somehow, which is what is left standing in the way of this being corrected. It does run pretty well in one direction, so I’m making progress on getting the last kink out.
Mike, the gears that the wheel axle stubs press into tend to split on these 70 and 44 tonners. A long time prob on these models. See if that’s your problem on the directional issue. Dan
I’m glad somebody mentioned cracked axle gears. I have 2 DCC on board ge 70 tonners and they both developed cracked axle gears. Here I thought I was the only one. Bachmann appears to only sell the complete trucks, and there is no guarantee the axles on those won’t crack too.
I’m kitbashing the shells into a centercab 80 tonner and will be looking for a more permanent replacement for the gears than simply new Bachmann gears.
I think the only source for the axle gears is Bachmann – and then only if you buy the whole truck.[:(] It’s possible something else fits, so would be great to hear from someone who has figured an alternative out.
I’ve used the last of mine from my parts loco and still may need another one, although I did get my third 70-tonner going this evening. If it’s the long side that cracks, it may be possible to fix them as I did per Graffen’s suggestion with the driveline cup by sleeving them with a bit of tubing.
Its been about a year since a set the project down so I had forgotten. I think NWSL makes replacement geared axles for the bachmann 44 tonner. About a year ago I called NWSL to ask if the those axles would fit the 70 tonner, and whether or not they were for the older two motor spectrum or the newer single motor version, which is what I have.
The fellow was very nice, but I came away not knowing for sure if they would work, since he didn’t know for sure either.
So if we can figure out if the axles and axle gears that Bachmann uses in the 70 tonner are the same as the 44 tonner, we can get nice metal uncrackeable replacements from NWSL. I guess the basic question is, has bachmann changed the axles on the trucks when they switched from the two motor to the single motor and do they fit the 70 tonner. I would suspect that they have not changed, and that the NWSL replacements probably fit all versions of the 44 and 70 tonner. I think the trucks are different between the two locos, wheelbase perhaps, but I would think the innards are basically the same.
Maybe somebody ought to buy on set on speculation and tell us if they fit.[;)]
That is intriguing. I know that the conversion half-axle set that NWSL sells for the 70-tonner is supposed to work with the 44-tonner, so they must be the same axle drive gear. I do know the mechanisms are the same for all practical purposes, other than the 44-tonner chassis is shorter. It looks to me like when Bachmann upgraded the old two-motor version of the 44-tonner, they simply used everything off the 70-tonner that applied. That makes sense, as why reinvent the wheel when the parts are already mostly on the shelf?
I won’t be checking on it right away, but when I do get around to ordering the driveline parts, I’ll check on this and let you know if it works…unless someone beats me to it.[;)]
The NWSL gears would still be plastic as metal would not work in this application.
I’ve also run across cracked gears in both the 44 and 70 tonners. I’ve also converted a few to HOn3 using the NWSL wheelsets. My fix has been to clean all of the old grease off and, if the crack has not gone into the gear teeth (normally, the crack is still on the longer shaft of the gear), use 5 minute epoxy. That has seemed to work well. Just make sure you use your NMRA gauge to set the gauge on the wheels within the 5 minutes!
Yeah, we can’t forget about electrical insulation – or there would be a meltdown when it hits the track.
I’d thought of the epoxy trick, but wasn’t sure it’d work on the plastic used for the gear. Certainly if you go all the way around the gear, that should keep the epoxy in place.
Everything I have read tells me they are made of brass with one wheel insulated from the axle. Apparently the axles includes wheels, with one wheel attached.
That will work with a standard gauge loco. It may not work with HOn3.
NWSL supplies half-axles designed to fit the B-mann plastic gear to convert to HOn3. Unless the NWSL supplied gear is an exact size replacment for the B-mann gear, then things won’t sit right or be easily convertible to HOn3.
As to the question of the 44 ton axle gears being the same as the 70 tonner I can say that yes they are. I have a newer 70 ton and an old twin motor 44 ton. The axle gears in both have split. I salvaged the good gears out of the 44 ton and used them in the 70 tonner. The trucks are not the same but the wheels and gears are. I e-mailed Bachmann and told them of the problem and asked if they sold the axles seperately but they said no you had to buy the complete truck assembly. They put out a defective product and won’t even sell the replacement parts. Hows that for customer service
Thanks Strider, that’s the answer I was looking for at least. Don’t know if that helps the OP or others.
I assume the NWSL 44 tonner axle replacements are designed to not cause electrical problems, so I’ll to use them on my 70-into-80 tonner project.
There is no reason to believe that new replacement bachmann trucks would not have the same split axle gear problem. I hear that bachmann will replace a defective locomotive, so if you get a new one with the gear problem, I suppose you can send it back and bachmann will replace it free. But there’s no reason to believe the replacement loco will not have the split gear problem eventually, etc…etc…deja vu all over again.
Strider does confirm what I’d heard, which is good.
Yeah, this rather frustrating. I converted my first pair of these 4 or 5 years ago. There were a few issues, but after getting them sorted out, thos two locos run great, if a little noisy.
One did split an axle gear a couple of years back. In the meantime, I’d bought a couple more 70-tonners in anticipation of converting two more to NG. I robbed a good axle gear off of one and used it to replace the split gear. It’s held up and the two original locos have otherwise been surprisingly reliable.
So I was using the 4th loco to build another NG conversion, which will give me 3 in service – maybe.
I don’t know if the gears in this one were made from a batch of particualt bad plastic or what.And I don’t mind fixing things. But I ended up having to sleeve all four cups in the driveline. After getting that sorted out, all four drive axle gears were split to one degree or anther. So this one was 8 for 8 in bad gears and driveline parts.
The bad part of all the axle gears being split is that makes it difficult to get a straight set of drivers when all need repaired to start with. That uses up all your extra tolerance for slop and, let’s just say, she has a pretty mar
I really like the 70 tonners alot. But won’t be buying any more I can tell you that, not if B-mann won’t back up they’re product. Proto had the same problem a while back but a least you can buy the axle gears for them. I also have a 45 tonner that I put a Tsunami in and hope I don’t lose that one to cracked axle gears too.