# Driving wheel is loose and wobbles



## Tallahassee Railroad (Dec 20, 2011)

Hi everybody, I have an Bachmann 4-8-4 J class engine and the back left driving wheel wobbles and comes loose when if runs. Eventually it comes loose enough that the engine can't run and the wheel can be taken out of it's axle. Anybody know of anything that can be done to help it?


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## shaygetz (Sep 23, 2007)

Welcome...:thumbsup:

I have done this repair several times with great success in both N and HO scale---so long as the drive wheel center is not damaged significantly out of round. I clean both surfaces very carefully with rubbing alcohol and then join the two parts with JB Weld. 

WORD OF CAUTION...steam models require that the drivers be properly quartered or they will fight each other, locking up the drive. They are 90 degrees of each other on either side, so study them carefully with dry fits before you commit. 

If it's a realitively recent model, Bachmann has an excellent warranty service that you'll want to take advantage of.


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## searstractorfan (May 30, 2011)

Hey I got one that does that too! its a great runner till that wheel comes lose.....mine is an 80's model when they were doing the excursion trains...


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## shaygetz (Sep 23, 2007)

The 80s models had a bad plastic used for the gears, your axle inside is split and unable to grip the driver properly. It got so bad that Bowser made a retrofit drive for it that you could buy.


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## searstractorfan (May 30, 2011)

huh...great info shay! is the bowser kits available still? ah i might send it off to NIMT to fix up later......


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## shaygetz (Sep 23, 2007)

Sadly, Bowser stopped making them last year and the remainder sold out quickly. They can be still found on eBay and at train shows.


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## Tallahassee Railroad (Dec 20, 2011)

Great, thanks for the help Shay. I'm still kind of new to model railroading, so I don't know most of the terminology. When you say...



shaygetz said:


> I have done this repair several times with great success in both N and HO scale---so long as the drive wheel center is not damaged significantly out of round.


What do you mean by the drive wheel center and it being out of round?


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## sstlaure (Oct 12, 2010)

The hole in the middle of the drive wheel that is loose. Is the hole wallowed out (made oblong/oval, damaged, etc.) So long as you have a nice straight hole through the wheel, shay's repair would work.


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## shaygetz (Sep 23, 2007)

Yup...what he said...:thumbsup:


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## Tallahassee Railroad (Dec 20, 2011)

sstlaure said:


> The hole in the middle of the drive wheel that is loose. Is the hole wallowed out (made oblong/oval, damaged, etc.) So long as you have a nice straight hole through the wheel, shay's repair would work.


Uh-oh, The loose wheel doesn't have a hole in the middle of it. Here are some pictures of it because I'm pretty bad at describing things.



















Will the repair still work on this kind of wheel?


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## Massey (Apr 16, 2011)

I can see the problem inthe second pic. The gear that the wheel attaches to is cracked. You will need to replace that gear. Have you tried calling Bachman and seeing if they still have a part that would work? I know they still offer the Class J engine but it has been updated with a new can type motor. Not sure if the drive gears will be the same tho. I would call them to find out. With my Class J from Bachmann I need to get a new motor or retro fit something in its place.


Massey


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## Tallahassee Railroad (Dec 20, 2011)

Massey said:


> I can see the problem inthe second pic. The gear that the wheel attaches to is cracked. You will need to replace that gear. Is this a bachman engine?
> 
> Massey



Yep it is. 

You mean the crack on the white casing, right?


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## Massey (Apr 16, 2011)

No there is a crack in the black part that the wheel actually pushes into. This kind of thing is not that uncommon, and pretty easy to fix if the parts are available.

Massey


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## Tallahassee Railroad (Dec 20, 2011)

Ahh, ok. Thanks for the help. I hadn't tried calling Bachmann yet, but I guess I'll give it a try. It's a used engine, so I didn't have much hope for it.


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## Massey (Apr 16, 2011)

Just see if you can get a set of gears for the drivers. They may be the same as the gears on the newer Spectrum Class J engine. 

There are several other Class J engines out and available so I would not spend too much money on this one. I used to have a Spectrum Class J but I did not like the way the tender attached to the engine. I sold it and bought a BLI Class J #611 as used in regular service.










I love this engine is it my all time favorite, and I model modern day!!

Massey


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## shaygetz (Sep 23, 2007)

Yours is the classic Bachmann failure. To electrically isolate the drive so that it could pick up power on both sides, Bachmann installed their drivers as inserts to axles made of a nasty plastic that failed early in the loco's life--sometimes while it was new in the box on the shelf. They inexplicably allowed this to go on for quite awhile, earning them the name "Botchmann". Parts are scarce, but contact Bachmann thru their website...you never know.


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