I’ve got a HO model of a Class 48/DL-531 Alco export diesel mounted on a K&M Enginneering Party HOn3 chassis. The vendor, besides being in Australia, is defunct. Normally a reliable, if somewhat noisy runner, it developed an odd short in the center axle of one of it two three-axle trucks. I’ve had it apart several time without real improvement
On the insulated side, you could see the spark of the short when it happened through the insulation. Something was definitely wrong. The truck had also developed an odd lope to it that was both visible and irritating. Problem is it’s not easy to get into the truck. It’s machined from brass with no obvious way to tear it down
. 
The axles are retained by pins driven below the axle center.
It looks like the pins can be driven back, which would free the drive axle from the gear train. I suspect a bearing went out or a retainer failed. Not sure this will give access to all the truck components, or not. Am I missing something here? Advice welcome.
Hi Mike:
I think the only way in is to remove the pins. I doubt that it will take much force. I suspect you will have to remove the towers from the top too.
Looks like its time for a good cleaning anyhow.
It must weigh a ton.
Dave
Yeah, there some grunge, it’s been in service for years without a teardown. Now I gotta figure out a small enough pin-punch to do the deed.
Got any small finishing nails? If so, grind the tip flat and see if they are small enough to go into the holes without getting stuck.
I suspect that if you can drive the pins out far enough to get a pair of needle nosed pliers on them that they will come out without too much force needed. If they come out really easily then I would suggest roughing up one end of the pin slightly so that when you put them back they will stay in place.
Please keep us posted!
Dave
Mike,
Those pins look to be the size of the metal axle’s in the old Athearn BB Plastic truck kits, or the Truck’s N’ Stuff axle’s. They would make a pretty good punch, it takes a lot of force to bend them.
Good Luck!
Frank
Dave and Frank,
Thanks for the tips. Guess a suitably sized piece of music wire would work, too, in a pinch. But I got to thinking I already have a suitable pin punch. I have a metal uncoupling tool that is basically a small diameter pin punch. Grabbed it and applied to the pin end. The pins were a press fit, but nit so tight you needed a hammer. Had it apart in a jiffy…
Then it was easy to see what the problem was. The insulating bushing, pressed into the wheel from the inside, had part of its flange broken off. That was allowing lots of slop and letting the shorts happen randomly.
Not having such a bushing handy, I filed the flange down so the remainder of the bushing inside the wheel remained.
Then I needed some to replace the insulating flange. Thought maybe a Kadee fiber washer might work, but the center hole was too big. So had to make my own.
I used a hole punch and a drill to produce a suitably sized washer by cutting it from an old slip-sheet.These are used in warehouses to handle product stacked on them with a special forklift, eliminating the need to exchange pallets. It’s tough stuff to resist being dragged across pallets and floors without tearing. I think it may be UHMW or something similar.
The resulting washer was too thick, as the gauge would be wide if assembled. I took the washer and ran it across a file. Being tough stuff, that took more effort than I thought, which is a good thing in that it means the washer will probably hold up. After several passes, I found the last little bit needed was to thin the wheel just a little by filing the wheel back.
Put it all back together and it runs sweetly down the tracks, without the wobble, too.[:D]
Nice work. Before I read down, I was thinking it was probably the insualtion around that wheel. Continuing to read, I think I would have given up on discovring the pins and switched to trying to figure out how to build a new chassis for it.
–Randy
Randy,
Yeah, turned out to be a piece of cake, but has had me worried recently. It had been acting up for some time, but so intermittent at first that there was little to go on. I finally was able to see it sparking between the wheel and the truck, which zeroed in on the location in the middle axle on that truck. But examination without a tear down revelaed nothing obvious. But the short worsened and became visible at the axle end, where the bushing was conducting the light from the short on the inside around the axcle to where it could be seen.
I actually have parts on order from NWSL to repace the Mashima motor with a Mabuchi and new flywheels. Not sure it really needs it now, it’s running so well. If it holds up, I may make a new chassis, if I can figure out suitable donor trucks. I may just make it a B-B whatever if I do, as modding 2-axle trucks is tricky enough. A 3-axle will be more of a chore, more than likely.
I’d like to source the bushings, as I suspect I have 11 more than will eventually need replacing. It’s a nice robust chassis, so really no complaints in general about it, as I’ve been running it for well over a decade. The design doesn’t like radii less than about 24" min, which may have been a contributing factor here.
With K&M out of biz for some time, if I needed another chassis, I’d turn to Hollywood Foundry, which is said to be superior to the K&M anyway.
Nothing quite as satisfying as fixing something yourself. Even better when the fix actually works.[swg]
Cheers, the Bear.
[(-D] After 8 hours and a lot of test running, so far so good. The next test is tonight when it goes “down under” so to speak with a passenger train on the Chama staging loop. It’s a challenging assignment, steep grades, a few curves and a turn and a half helix. Good performance is a prerequisite. My back hates going there, so I like to have the locos able to go there and back without human intervention.
Our hobby might be one of the last refuges for the classic “garage tinkerer” that this country used to extol as being central to our national self image.
If nothing else this again demonstrates that necessity is the mother of invention.
Dave Nelson
Mike:
Like Bear said, there is a real sense of satisfaction when you can fix things yourself.
Glad the pins came out fairly easily.
Dave
Me too. Things tend to go pear-shaped when I have to get out the BFH. When the first one pushed right out, I knew I gonna be OK
I think our supply of tinkerers – or, as I prefer, “shade tree mechanic”[D)] – has been outsourced like much of the rest of our nations’ natural and human capital.
Dave Nelson:
You bring back memories of my beloved '68 MGB. I bought it as a rusted out wreck. I managed to keep it running for another 10 years, although it never got too much above the status of a ‘wreck’. I think I rebuilt the engine at least three times. My brother gave me a copy of the BMC tuning manual so it was a little tricked out and went like stink, at least by the standards of the time. I had to jury rig the body to keep it from collapsing on the road. Painted the body with a brush in the colours of the British Ensign! Best of all, no muffler! It looked like there was a muffler but a friend of mine welded up a muffler case with a straight pipe right through it. Sounded way way better than the current Japanese stuff with big tail pipes.
[#offtopic]
Sorry. Couldn’t resist.
Dave