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Funit
Switcher
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 Posted - April 05 2016 : 05:21:03 AM
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Some of the plastic (insulated) rear drive wheels on the older Tyco/Mantua diesel engines can develop a crack which extends from the axle hole to the outer rim of the wheel. These are the wheels with the rubber traction rings. The crack usually occurs along one side of the original mold line. It's caused by the pressure of the press fit of the wheel on the axle. The crack can make the plastic wheel slip on the axle which results in a loss of traction.
What would be the best glue for repairing these cracks? Would thin CA be a good choice or should I use a special plastic glue or solvent? I assume that the wheel should be removed from the axle before the repair. I would probably apply some compression with a small clamp or miniature vise grip to the outer rim of the wheel to ensure that the crack is closed while the glue is setting. There is also the possibility of carefully heating the plastic wheel with a heat gun to close the crack before gluing.
After repairing all the cracked wheels, I would make the axle holes in all of the plastic drive wheels slightly larger. This would permanently relieve most of the press fit stress, so the cracks didn't keep occurring. I would reattach all the plastic wheels to the drive axles with a little CA to gurarantee that they don't slip.
Any suggestions would be appreciated.
Thanks
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Country:  USA ~
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Posted - April 05 2016 : 09:26:26 AM
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| I've caught a few Tyco diesels with the hairline crack forming before any slipping occurred. A little drop of super glue seemed to keep them together. I'm not sure what the longevity of that repair is though.
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Posted - April 05 2016 : 10:24:52 AM
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I'd avoid the heat gun. I think the plastic could warp in some unexpected directions when heated.
Carpe Manana!
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Posted - April 05 2016 : 10:25:59 AM
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the worse I ever had with Tyco diesel motors is that darned Pinion Gear slips off!  
have a CP loco like that but atm its in pieces!
gotta get friend to help me fix it sometime
& I will take pix of how he gets Pinion Gear to stay on
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Posted - April 29 2016 : 04:57:27 AM
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I have a similar issue with a Rock Island Shark which I recently picked up for $8 (and $32 shipping from the US, go Australia!)
The problem was not a cracked gear or wheel this time, but a slightly offset wheel which causes the loco to wobble and stall at low speed due to the gear moving up and down - not sideways (the motor runs fine when I remove this wheelset). This is a thin axle loco, not the older thick axle type.
With this loco I had to replace the rear wheelset as well, as the plastic wheel had a broken flange and the loco would come off as soon as it hit a curve. As I had a spare Lima passenger car wheelset lying about, that had to do - I had to slightly bore out the axle holder to get it to fit (hmm, Baldwin, Lima...) but other than that it was perfect.
As for cracked gears, that would be my old Bachmann F9, which managed to crack both reduction gears(?) and break a drive wheel gear tooth (inner axle), which is now being driven by the rear axle only and making a beautiful clicking sound every time the axle rotates. Conveniently, Bachmann themselves also ran out of spares for the old pancake motor chassis so I'm out of luck there too!
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Country:  Australia ~
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Posted - April 29 2016 : 09:51:52 AM
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| regarding that Bachmann f9, your best bet would be to find a newer Bachmann f unit and swap shells. those pancake motors as used by Bachmann are some of the least durable drives out there. why go to all the trouble to rebuild something that is going to fail again on you anyway, when you have a cheap, readily available drive that is designed to fit that locomotive. some minor shell mods may be required, but in the end you will have a reliable locomotive that runs the way it should.
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Posted - April 30 2016 : 04:47:10 AM
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| Hehe, if I bought another complete loco for next to nothing I would probably end up using that one as well, I simply can't think of destroying them!
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Country: Australia ~
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Posted - October 03 2016 : 8:30:15 PM
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I would stay away from CA glue( because it is brittle, and can crack easily), and go with the prefered Plastic cement, or just epoxy.
In fact, use plastic cement whenever you can. Plastic cement "melts" the plastic around it and when it dries, the "melted" plastic joins together, making an unbreakable bond. Plastic cement will only work for 80% plastic types, not all.
Charles
If I can't fix it, I can fix it so it can't be fixed.
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