Kato GS4 Driver Replacement Tutorial

[strummer]

  Victor , Peteski , Max , I read all of your rebuilding / improving comments on different locos with great interest . You always seem to find innovative and practical solutions to the problems .

I'll second that; much better than what's on TV....

Mark in Oregon

[Dwight in Toronto]

This thread from mid-2015 is wonderfully timely, given that my upgraded GS4 drivers just showed up yesterday. 

My GS4 is from the very first, original production run.   

The replacement drivers appear to be in good order - the rims are perfectly pressed onto the wheels, wheel spacing appears to be in compliance with my NMRA gauge, and all four sets roll beautifully without any wobble (these were apparently distinct shortcomings nine years ago).

I’m curious if anyone knows if the current replacement drivers still need the styrene ‘U’ channels as devised by Max, or if the bearings might now be of a better fit/design?

Thanks in advance for any advice.

[Hedron]

I'll join the thread necromancy by adding that I happen to have the same question. I have an eBay special GS-4 and a set of drivers just arrived from Kato waiting to be mated.

[Mark5]

I’m curious if anyone knows if the current replacement drivers still need the styrene ‘U’ channels as devised by Max, or if the bearings might now be of a better fit/design?

@mmagliaro

[peteski]

I’m curious if anyone knows if the current replacement drivers still need the styrene ‘U’ channels as devised by Max, or if the bearings might now be of a better fit/design?

Thanks in advance for any advice.

If you review the initial post, the styrene inserts are specifically recommended for the new (currently sold) driver set

See http://www.maxcowonline.com/photohost/katogs4/gs4_14.jpg

[mmagliaro]

The problem was that the new drivers had bearings with smaller "ears" on them, and could pop out of place from the frame slots.  The frames you have are the frames you have, and they haven't changed.
I don't think there's going to be any changes to what I wrote in 2015.

[Dwight in Toronto]

Ok, fair enough.   I was hopeful that MAYBE, with some of the other deficiencies having apparently been addressed, that perhaps improved “ears” might have been incorporated on the bearings.

I will include the MaxFix in my upgrade.

[mmagliaro]

Some people have anecdotally mentioned in the forum over the years that they managed to just put the new drivers in and they worked.
All I can tell you is that on 5 (or 6?) of these that I did for people, there was always one problem axle that would come out of position while the engine was running.  Sometimes, I could get it in there 'just so' and it would work for a while, but then pop out and jam.  I reached a point where I decided the fit was so dicey that it wasn't worth the risk.  Making up that little styrene U-shaped thingy isn't too awful bad. It's cheap insurance.

[nightmare0331]

basically, I've found it's only the rear driver that needs a spacer installed.

in order to keep the bearings from slipping inwards, I just use a piece of plastic swizzle stick that's cut small, then slit down the sides, so it fits over the axle between the two bronze bearings.

Crude, but effective in keeping the rear axle bearings from folding in on themselves.

Make sure if it's a 126-0301 that you either install or modify the existing spacers for dcc operation.

Ah the GS4.  I've fixed more of those than I'd care to ever remember.

Enjoy!

Kelley.
www.dufordmodelworks.com

[peteski]

Yeah, on the first run of these models, if they are converted to DCC you will likely end up blowing up the decoder when the rear drivers touch the motor sub-frames.  The washers Kelley mentioned have to be installed.  There used to be a tutorial on Kato website showing how to install those washers.

[mmagliaro]

basically, I've found it's only the rear driver that needs a spacer installed.

in order to keep the bearings from slipping inwards, I just use a piece of plastic swizzle stick that's cut small, then slit down the sides, so it fits over the axle between the two bronze bearings.

Crude, but effective in keeping the rear axle bearings from folding in on themselves.

Make sure if it's a 126-0301 that you either install or modify the existing spacers for dcc operation.

Ah the GS4.  I've fixed more of those than I'd care to ever remember.

Enjoy!

Kelley.
www.dufordmodelworks.com

Oh yes... I should have mentioned.  I never had to do all four axles.  One axle is geared with a tube, so that one isn't
going to have the bearings creep in anyway.  It was always just one or two, and usually just one, that was the
problem.

[Dwight in Toronto]

I’m so glad that Kelley shared his tips.  Knowing that he has serviced untold hundreds of these locos ( I’ve watched all his videos), I’ve been curious about his ‘bearing retention’ approach.  He seems to be a very busy guy, so I didn’t want to intrude and ask him for advice.

Sounds like it can’t get much simpler than the swizzle stick!  @nightmare0331 , if it’s not asking too much, any chance you could whip up one of your “hastily shot, poorly narrated” videos (his descriptors, not mine!), or even a simple pic or two showing the high-tech swizzle stick approach?

I’ve got a pretty good idea of what you describe, but pics are always helpful. 

Fwiw, I applied Kapton tape to the susceptible subframe when I first equipped my GS4 with dcc all those years ago.  I did the ESU 58731 sound and LED’s upgrade (two in the front, one in the tender) about a year ago.

[Dwight in Toronto]

One more question … I assume that the driver exchange procedure can be done without taking the shell off?

[Dwight in Toronto]

I just checked my GS4 model # … it’s a 126-0302.  How might that differ from the 126-0301 that Kelley mentions?

[Dwight in Toronto]

I completed the install of the upgraded drivers. 

I’m not sure if my bearing retainer approach on the rear-most set of wheels (the ones with suspension) is considered appropriate or not.  Lacking a plastic coffee swizzle stick, I used a small piece of styrene tubing.  What is not visible is the back side of the tubing where I bezelled a narrow ‘V’ shaped channel, and then cut a fine lengthwise gap/split in the tube, which enabled a gentle push-down “snap” fit over the axle.  The suspension action was still functional, and the wheels rotated freely, so it looked workable:



I gotta say, re-inserting all those tiny pins was a real treat … holy shmoly.  I put everything back together, tried it on the test loop, and got about one-half revolution and things stopped moving.
It was the square-pegged retainer - needed to be turned 180 degrees and reinstalled.

Ran the loco forwards and reverse a number of times, at various speeds, and all seems good.  Fingers crossed!