Split U-joint cups on Kato RDCs?!

[peteski]

I was messing around with one of my RDCs and I noticed a that it was infected with Bachmannitis!

Both cups (on the motor shaft) are split - the one in the photo is the more severely split one.  It doesn't (yet) seem to affect its performance but if the split continues to get larger, who knows what will happen.  Funny thing is that only the cups on the motor are split. The ones on the truck worms are fine (but they are different moldings).I have about a dozen of RDCs but I haven't looked at any others yet.

Has anybody else experienced this? I'm really surprised to see this on a Kato-made model.

[Lemosteam]

Man, that looks like a press split right from the factory.  Are those the clearance units you announced a while ago?

[kalbert]

My Kato GP50 did something similar a few years ago, eventually started slipping and fell apart. I replaced the whole shootin match with a little silicone fuel hose and it's worked well. That was a considerably shorter length than what you probably need. I wonder if you could use two short lengths of hose as couplers, and a length of brass rod between for a drive shaft?

On the other hand, it looks like maybe parts are available right from Kato to fix it.
http://search.cartserver.com/search/search.cgi?cartid=s-1078&keywords=NRDC&maxhits=100&go=List+Parts&bool=AND&bool=AND

[peteski]

The model is basically unused (bought it at one of the fire sales for $25, so yes, it was a clearance unit).  I'm sure it's been sitting in a warehouse for years since Kato has not made any RDCs for quite a few years.  But I don't know if the split happened right at the factory or after sitting at a warehouse for some years (since the plastic was under stress for all those years).  How can one tell whether this happened right at the moment it was installed at the factory or later?      Or do you think that Kato noticed that their RDCs have this flaw and asked dealers to clear them out?     That sounds a bit far-fetched to me. Maybe you're right, maybe not.

I'm still interested if other RDC owners seen this on their units.

[peteski]

Thanks Kyle!
At this pont it is not slipping yet (and I have to eventually check all the other RDcs I have).  If many of them have a similar problem I'll contact Kato USA to see what they can do for me.  The silicone tubbing and/or buying replacement parts could also happen eventually. This model is unlike the one you have where the long shaft connects between the motor and a worm which is part of the truck. But the distance between the worm and the motor shaft changes considerably as the truck tilts forward or back. The truck's U-joint end has no play in it. The motor end has all the play in it. So replacing it with tubing might not work well.

[Lemosteam]

Maybe Kato noticed and test ran them, and authorized the clearance.  I would have expected them to make potential buyers aware...  I suppose the plastic could have shrunk over time too.  This would also explain the crack only being on the motor shaft end as the slip joint pocket diameters would just shrink, whereas the motor shaft would prevent that.  Hmmm....  I wonder if a drop of ca would seep into the crack and prevent further splitting an slip, that is if Kato doesn't come through.

[kalbert]

Ahh, I wasn't sure how different the mechanism was on one of those, sounds like it's really different.

I'd guess that Kato didn't test run any of these or open the box and take them apart for inspection, had no idea what condition they were in, and just wanted them off the shelf. Nobody's probably looked inside that unit since it was assembled.

Having replacement parts available is a winner though, even if every one of your units is broken the same way it looks like they're only a couple bucks. Could be SOL with a Life Like unit!

[randgust]

I'm pretty sure the clearance was purely due to massive inventory issues, not due to any known flaws.   Because Japan likes MU passenger train cars, they figured the same had to be true in the US, that's my speculation.

[SP-Wolf]

I have a few of the Kato E9's with this issue. HMMMMMMM.....

Interesting,
Wolf

[kornellred]

I just took a look at one of my Kato RDC motors.  Both of the U-joint cups are split exactly the same way as the photo illustration above.  Apparently, this condition is going to prove to be widespread - like the slipping gears in the NW2 drivetrain.  I fixed that by roughing up the shaft and coating the roughed up area with ACC and sliding the gear back into place.  I may do that to the RDC motor U-joint cups as well.

[peteski]

Interesting...
Looks like I'll have to check (at least some of) my other RDC units to see how the U-joints cups look in them.

I also don't see Kato trying to lowering the price on them because of a known defect. After all, it seems that other Kato models also have this problem.