# USA Motor Block & broken gear.



## John J (Dec 29, 2007)

I have three NW-2s. I took the motor blaock apart to clean and lube. I found of the gears on the wheel axels broken. 

This is the style were the axels go all the way out to bearings in the side frames 

This gear is also a isolator for the two sides for track power pick up.

Has any one found a way to fix this? 

For right now I set the gap and then put some Loctite Supper glue on it.


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## Trainwreckfilms (Aug 19, 2009)

Ive replaced all the wheels on my Geeps and NW-2's because of the gears snapping... Just purchase new ones... Welcome to Railroad Maintenance! No fix for me just buy new ones...


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## Greg Elmassian (Jan 3, 2008)

If you want to fix them, pull the axles out of the gear. 

Wind some fishing line really tightly on the axle. 

While holding it tight, coat with epoxy and let set. 

Then put the axles back in. 

Regards, Greg


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## toddalin (Jan 4, 2008)

I don't think I have any USA engines that don't have cracked gears, and there is no way I could/would afford to continually change out all these axles.

I use a length of brass (IIRC) 7/16" diameter tube that is just shorter than the cracked side of the gear. I use a tubing flarer to _slightly_ flare one end. This sleeve is then pressed onto the gear in a vice. The flare keeps the brass from just digging into the gear's plastic as you press it on. The axle is then pressed back into the gear. This is a permanent fix and the axle will not slip on the splines on the fixed side afterwards.


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## Greg Elmassian (Jan 3, 2008)

That's what I do, I have a set of brass pieces made just for this purpose. Tony Walsham used to sell them, I bought the rest of his stock. 

I'm good for the next 10 years. 

Greg


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## Dan Pierce (Jan 2, 2008)

USA axles are $10, complete motor block $35. 
I replace the whole block, you get a complete running block for the $35. Plus the old block is a keeper for spare parts!!


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## W3NZL (Jan 2, 2008)

*Replacing the axle, or the whole motor block isn't the answer, the new axles and *
*motor blocks with the supposedly split **proof gears, split just like the old ones !!!!*
*When this problem first arrose a few years back, and when we found out that U *
*couldn't buy the gear separately, U had to buy a whole axle, at $9 a copy or whole*
*motor block at $28 a copy, and U had 9-10 USA engines, all with the same problem, *
*it was going to cost U several hundred $$ to fix all these things, plus the fact that *
*there was no guarantee that it wouldn't happen again !!!! An it has !!! Several folks, *
*including myself, Tony Walsham was another I know, and there were others too went *
*to work on the problem, I think most of us came up with about the same solution to *
*the problem, make up press-on sleeves for the gears that could be re-used when the *
*gear had to be replaced... I wrote up a couple of "how-to" articles at the time and posted *
*the stuff here on MLS, probably still in the old forum archives somewhere... I wound *
*up using 6061-T6 tubing to make my sleeves from, 7/16 w/.060 wall, and bored to the *
*proper ID to fit snugly on the gear... I suggested that some enterprising young fellow 
around **here with a wife, 3 kids, a big mortgage, an a decent lathe could supplement his 
income **nicely making these things up, in quantity they could be produced for about 20 
cents **apiece.... Sell a set of 8 for say $10, ****, make it $12 shipped in a padded envelope 
with **a set of instructions... What a money maker, but nobody ever did it as far as I know.. *
*Heres a pic of what I wound up with for **my efforts...*
*Paul R... 








*


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## Greg Elmassian (Jan 3, 2008)

One note, some of the smaller motor blocks have very tight clearance, you need very thin wall tubing, and even then may have to grind away some plastic in the motor blocks... needed to do that for my 44 tonner. 

Regards, Greg


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## aceinspp (Jan 2, 2008)

Well lets see now I know where to go to get my parts for the repairs.







Later RJD


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## John J (Dec 29, 2007)

Posted By Greg Elmassian on 27 Feb 2010 12:10 PM 

One note, some of the smaller motor blocks have very tight clearance, you need very thin wall tubing, and even then may have to grind away some plastic in the motor blocks... needed to do that for my 44 tonner. 

Regards, Greg This is true. I was hoping to put a samll wire tie over the gear but whne I went to put it in the block again There was no room for it to turn. 

So for right now I just gooped it up with some thick Super Glue brom Loc Tite.

Speaking of Super Glue. 

Take a look at Home Depot. Loc Tite has come up with several differednt versions of Super Glue. 

They work quite well.

The make one that is rather thick which is what I like. It has a tendancey to stay where you put it.

They aslo make one that is resistance to shock. That is what I used on my gear assembly


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## W3NZL (Jan 2, 2008)

FWIW to anyone who is interested, 
The Aristo FA drive gears were identical to the ones used in some of the USA units, and can be bought
separately... Best of all, the Aristo gear don't split !!! I just can't remember which one it worked in though,
I think it was the 44 tonner block, I installed some in a couple of USA engines a long time ago, just don't 
remember anymore which engines it was, I do remember that they wouldn't work in the larger "GP" blocks 
though... Maybe one of the younger minds around here can shed some light on the subject, at my age, 
memory ain't a long suit... hehe
Paul R...


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## TonyWalsham (Jan 2, 2008)

It was Gordon Watson from Argyle locomotive that made up the tubes for me. They were expensive to make as a commercial proposition. 

Fortunately K & S tubing make exactly the correct diameter tubing. Nice and thin too. 
The biggest problem is cutting the tube to length. It would best be done by using a NWSL roller cutter. 

Once done they are a simple press fit over the cracked axle extension. I used to flare the inner end just a bit to stop them catching the plastic and then tapped them on *GENTLY*. 
Replacing the metal axles is best done in a drill press. Both of them at the same time. Be very careful that both axles go in evenly. Be very careful not to damage the thin plastic membrane in the middle that keeps the two metal parts from touching each other. 
I did take a series of pics and published them on the Net. If I can find them I will post a link.


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## lownote (Jan 3, 2008)

I bought my first usat engine, a 44 tonner, a year or so ago. It arrived with all the axle blocks split--unused, in the box! I sent it back, they fixed it. Now it has cracked gears on at least one block. I need to tear it down and fix it. 

It's completely astonishing that USAT has had this problem for what, a decade? Two decades? and has done absolutely nothing to address it. It's not rocket science


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## Trains (Jan 2, 2008)

I went with the brass tubing for mine, easy to do.


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## W3NZL (Jan 2, 2008)

Lownote, 
Its been going on since 98-99 when they first came out with GP-7,9... Far too long for sure... 
3-5 years ago I handed Charlie a gear, with the sleeves like U see pictured above, and explained 
to him what it was all about ... He thought it was a great idea, especially when I told him that with
an automatic screw machine set up to produce them, the cost would only be about 10 cents apiece, 
he was going to look into it... Looks like he didn't... Last year at the east coast show in York, don't 
remember whether it was the spring or fall show, I was perusing the goodies in Charlie's booth when 
some guy walked up to Charlie and started reaming him a new one over the split gears, he'd bought 
all new axles for all his engines and installed them, now they were all splitting again!!! The guy was 
livid, and who could blame him, this has gone on far too long.... Had a call from an LS dealer a few 
months ago, he'd heard that I had a fix for the split gears, and would I come over and talk to him 
about it, customers were driving him nuts over the problem, I took a couple of the sleeves and gears 
over to him, he too liked the idea and pleaded with me to produce them for him, but I told him that 
I've been retired for almost 20 years and wasn't interested in job, I left the parts I'd brought with him, 
maybe he could find someone locally to produce them, don't know whether he did or not... Like I said 
in my earlier post, somebody needs to produce these things for sale, after 12 years its pretty 
obvious that the mfgr isn't going to deal with the problem...
Paul R...


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## toddalin (Jan 4, 2008)

I use the 7/16" brass tubing on my 44-tonner with no problem.

As Tony noted, the biggest problem was getting a clean cut of the brass tube which is hard to do with a hack saw, then trying to clean up the cut without distorting the small piece (been there/done that). But the answer is to use a tube cutter as is used for cutting automotive fuel and brake lines. You just spin it around the tube and it cuts cleanly as it goes. Get a small one that let's you get closer to the edge of the tube. These "brass bands" are pretty short.

I just do these in my vice. The other issue is getting the axles to press back in the same on both sides of the gear so the gear remains centered while the wheels are pressed into gauge. Once you get the first side in, it is harder to get the second side started without pressing the first side in too far.

What I do is get the first one in and started, but don't press it all the way into place. Wrap some copper wire around the axle you just did between the gear and the wheel and this will serve as a "stop" to keep you from pressing in the first side too far while trying to get the second side on. Also, use a nut/thick washer/spacer between the wheels and the jaws of the vice so that you press around the circumference of the wheel, and not directly on the end of the axle that protrudes through. Once you get the second side on and started, you can unwrap the copper wire from the first side, as necessary, to get both sides to press in pretty much the same.


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## TonyWalsham (Jan 2, 2008)

OK.
I found the pics.
They are in sequence order. The urls will explain what to do.


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## Nicholas Savatgy (Dec 17, 2008)

Nice pictures Tony, should i ever need to repair a set i will use this method. Thank you.


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## Greg Elmassian (Jan 3, 2008)

They are on my site also, under USAT motive power, with due credit to Tony. 

Regards, Greg


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## Randy Stone (Jan 2, 2008)

Now, is the gear itself splitting or just the ends where the sleeves are getting pushed onto? 

This looks like something that should be done before they crack, especially if the diesel is going to be used a lot. 

So, we have the NW2, 44 Tonner and the GP7/9 listed. 

Are there others with this same issue? 

Randy


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## Greg Elmassian (Jan 3, 2008)

All of the diesels are subject to this. 

There is a one-piece casting with the gear and the 2 "tubes" on either side to hold the axles. 

Regards, Greg


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## TonyWalsham (Jan 2, 2008)

Randy, 
I believe every USAT loco suffered the same problem up to the GP30. After that USAT changed the knurling on the wheel shaft and supposedly fixed the problem. 
I have never seen it on later models, but, undoubtedly they *could* be just as bad over time.


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## Nicholas Savatgy (Dec 17, 2008)




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## Greg Elmassian (Jan 3, 2008)

I have seen the "improved" knurling, it was on the new axles I purchased, both for F units and PA's... it's different but I have had split axles with this new type of knurling. 

I don't feel that the problem has been "fixed". (I do have a number of USAT diesels) 

Regards, Greg


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