2343 Motor Bearing Repair...But it worked!

dkdkrdOGR Forum Member

I had acquired an unmatched ABA set of 2343's from an old collection. The powered unit seemed to be in pretty good shape...clean battery cavity, perfect E-unit function, working horn/relay, cosmetically in a C6/7 realm (IMHO, of course.) Cleaned the old lubes off motor and truck gearing, Red-Tackied and LaBelled, cleaned the commutators, etc., etc, reassembled and ran it on the rollers. Seemed OK...usual 'growl'...or so I thought.

But another, more experienced person listened and didn't like the sound so much. Suggested running it on the layout for a longer period. He was right: It wasn't copacetic. The rear motor was hotter to the touch, there was a 'dry-bearing' buzz...random, not consistent...and the longer she ran it seemed like she developed a jerky-hitch...not necessarily simultaneous with the random buzz.

Tore it down further. And, yes, one of the axle gears in the rear truck was 'shot'...cupped teeth. Decided to also replace the truck armature bearings and the motor idler gear/axle assembly at the same time. Reassembled, tested. Maybe better, but not 100% so. The ear said that perhaps the rear motor was suspect after all. And it became apparent from the amount of radial play of the motor end of the armature shaft that we perhaps had a motor bearing problem all along.

Now, I had never torn down a 2343 motor assembly to remove the armature before. I know Lionel probably had or advocated some fancy set of tools/fixtures to do so. Not in my workshop, though. So, with advice from my friend and help from the wife, I used a drift pin and hammer to free the armature from the gear on the end. Got out the vernier calipers. And... eek !!

The armature shaft was a consistent 0.185" OD (say, 3/16" OD). The front bronze bearing checked 0.189" ID...not that bad...considering that the bearing regions of the shaft showed that oiling of the rear motor armature shaft may not have been a maintenance priority in the life of the engine!! rolleyes

Then, I checked the ID of the rear (motor end) bearing. HOLY CANNOLI!!! 0.195+" I.D.!! Buzz much??!!! Poor maintenance??? Well, DUH!! My go-2 source for parts showed having the front replacement bearings in stock...but not the rear bearings. What to do, what to do?....

Two beers and a good night's sleep later and I had a thought: Since the armature shaft is essentially 3/16" diameter, and since K&S makes brass tubing in telescopic sizes, could the useless oilite rear bearing be re-bored for a brass tube liner to effect a new bearing?? I had a good length of K&S 3/16" tubing in the scrap box...a perfect fit to the 2343 armature shaft! I had a complete set of numerical drill bits...hmmm.

So I turned to the drill press. To try reboring the rear motor bearing while keeping alignment with the front bearing, I mounted a block of wood to the drill press table. I then bored a deep 3/16" hole in the block, inserted a piece of 3/16" drill rod with about 3/4" exposed. Set the motor block vertically with the front bearing over the exposed drill rod, and I was ready to try step-drilling the useless rear bearing to accept the 7/32" OD brass tubing. It took about 4 steps, but I ended up with the brass tube (about 3/8" long) being a light press fit into the bearing remnant.

Alignment of the front and rear bearing holes was not perfect, but close enough to show that I was nearly there. A fresh 3/16" drill bit run at slow speed through both front and rear (repaired) bearings simulanteously, and the armature shaft spun freely without wobble. It seemed like it might work!

Reassembled, lubed, roller tested, and then layout tested for 1/2 hour and...

NO BUZZ, NO HESITANCY, NO OVER-HEATING...a new kitten-like 'growl'!!! thumb

I know it's not the way purists would approach the problem. Frankly, I have no idea how I would've removed the rear, much less the front, bearing from the motor block without special tools, instructions, training...strange prayers at bedtime!...whatever!! And, I have no idea how long the repaired motor will last in its re-built form. Perhaps it'll outlast me. I'm happy. She lives! nod

So, maybe this is not a unique solution. Perhaps others have used this technique before. Maybe it'll help someone else. FWIW.

Thoughts?

5/24/2311:34 AM

❤️ 8

Original Post

Replies sorted oldest to newest

Richie C.OGR Forum Member SUPPORTING MEMBER

Much like sleeving an engine block, but a good exercise in problem solving - congratulations.

Did you leave the tubing as a press fit in the inner bearing race or did you secure it with epoxy or something similar ?

5/24/2311:45 AM

❤️ 0

dkdkrdOGR Forum Member

@Richie C. posted:
Did you leave the tubing as a press fit in the inner bearing race or did you secure it with epoxy or something similar ?

No CA or epoxy. When I had successfully removed the armature shaft, I was so happy that I gave the motor block a 'bath'...to clean out the gunk that had accumulated between the front and rear bearings and out at the narrow end where the two spur gears had been Red-and-Tackied a couple of times over. Then as I bored out that rear bearing with the series of numbered bits, I used a Monoject 412...

...to flush the chips out...thoroughly...in that cavity between bearings. Believe me, that oilite bearing had been flushed so many times, coupled with a prior lifetime of probably little oil added!, that the bored bearing remnant was pretty 'dry'.

But, as I stated, the final bore of 7/32" created just enough of a press fit of that piece of brass tubing that I decided to let it go at that. That was just a bit of serendipity, I suppose. And, by press fit, I'm saying I had to move it to final position, flush with the bearing end adjacent to the armature thrust washer, with a wood dowel and a couple of taps with a tack hammer.

Good analogy, BTW, on sleeving an engine block! Never having done that myself, but hearing about it during my first career of 31.5 years in an automotive component division, it's a good analogy of what took place. Hey, maybe that's what 2 beers and a good night's sleep will dredge up from the dusty corners of 78-year old cranial matter!!!

Just got through running the ABA around the layout for about another 1/2 hour. Gee, it surely runs sweet and makes this guy smile!! It's steaks on the grill tonight!!!

Attachments

Show

5/24/232:24 PM

❤️ 5

TonkaNutOGR Forum Member

Well done Ken. I like the way you write (detailed with plenty of humor) and also the way you go after a problem and use what you have available to solve it. Well done!

5/26/2312:42 AM

❤️ 2

dkdkrdOGR Forum Member

Thanks, TJ!

BTW...to add some final punctuation to this 2343 ordeal, the beasty gave me one more cardiac thrill while running the layout Wednesday evening. As it rounded a generous bend at the utilities end of the layout it came to a sudden stop! (Dontcha just love something like that?...that warm fuzzy flushy feeling as you stare in disbelief at the lights-out engine, dead in its track, the ATSF insignia almost resembling a smirk on its rosy face???!!! mad )

Well, the circuit breaker on the MRC AH601 said 'We have a short, Houston!' Picked up the lead unit. The blackened front pilot coupler shield fell to the floor! OK. That's one of the fastest short circuit diagnoses I've experienced in the last 20 years!! So where is that tiny short screw that bailed out of its job...somewhere along the ROW?? Logic would have it be within the last 1-2 feet of its final stop. But, apparently not.......of course! shake

Retrieved my handy-dandy extendable magnet wand and began trolling the track. BINGO! thumb Thar she be!...about 3 ABA-lengths prior.

I had a foam cradle and screwdriver handy at the control station. I decided to just flip the unit on its back, refasten the shield and resume running...not taking the time to remove the horn battery! I swear, that engine was trumpeting wailing a monotonic raspberry as I fastened the shield in place!!

What a pal! Two old pharts keeping each other alive with our failings, foibles, ....and enjoyable attention!