# Bachmann K7 - Fix for Locking up when reversing.



## bobgrosh (Jan 2, 2008)

At least two other people have reported this symptom.
The loco runs fine in one direction. Stop loco and reverse direction, SOMETIMES the loco locks up and raises the second driver. A couple reversals and the loco heals itself. Can happen either when going forward and reversing or going backward and reversing.

The following is just *ONE* cause of this symptom.

I sketched in hidden parts of the reverser in the picture of the right (engineers) side of  the K27.









Look close at your loco, Make sure the screw is not missing on the engineers side.

ALSO!
Look close at BOTH sides and make sure the blue part goes through the center of the green part. If not, remove the screw. Once both sides are properly engaged, install the screw.









B0B


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## Curmudgeon (Jan 11, 2008)

Close but no cigar.


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## bobgrosh (Jan 2, 2008)

TOC,
Are you saying this can't cause the problem?
- or - 
Are you saying that you have found another likely cause.

I hear rumblings about loose counterweights, but, so far I have not had them cause any problem. 

But then I only have one Kay and only 3 hours to look at it. So Please enlighten us mortals.

B0B


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## Greg Elmassian (Jan 3, 2008)

I think the latter, maybe this will help.










Regards, Greg


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## chuck n (Jan 2, 2008)

After 10 or so hours of running without a problem, my K has developed a hitch in its git-a-along.  If it runs at all it sort of hops down the track.  More likely than not it won't move in either direction.  It appears that I have the same problem the Greg photographed in the previous post.  There seems to be a lot more play in the wheels and counterweights.  There is a modification over in the Bachmann forum that I'm going to try as soon as I can get some .007'' brass.

Chuck N


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## Curmudgeon (Jan 11, 2008)

Mine took .008"


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## chuck n (Jan 2, 2008)

Thanks, TOC

Sometime I'm going to learn not to buy a Beta.  I should wait for the rerelease, but it is one beautiful engine.

Chuck


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## TonyWalsham (Jan 2, 2008)

Posted By chuck n on 01/21/2008 5:30 PM
Thanks, TOC

Sometime I'm going to learn not to buy a Beta.  I should wait for the rerelease, but it is one beautiful engine.

Chuck


Chuck,
Everybody gets a beta./DesktopModules/NTForums/themes/mls/emoticons/crying.gif


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## blackburn49 (Jan 2, 2008)

Fortunately my K-27 is an Accucraft. Now if I can just find a use for it . . .


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## chuck n (Jan 2, 2008)

Tony:

I think that there are more Betas from some manufacturers that others.  

I have three Bachmanns that I run regularly, a climax, connie and the new K-27.  Only the climax has not had a significant problem.  After the Connie stopped, I used TOC's suggestions for the Connie gears, and I am in the process of trying to fix the K-27.  I also had trucks on the Connie tender break.  No replacement trucks were available from Bachmann.  I now have Accucraft trucks on the tender.  I also have LGB, USAT, Accucraft and Aristrocraft engines.  Of 30 plus LGBs I have had to return two, one for a failed sound unit, and one for design flaws in the motor block (the original red and green mogul).  Both of these were repaired and returned.  After many years of heavy use I've had to replace gears and motors in a couple other moguls.  LGB always had parts and getting them from LGB or the LHS was never a problem.  The only other engine I had to send back was the Aristocraft Mikado with a broken axle.  Aristo returned the engine in a timely fashion and I haven't had any further problems.  Unfortunately, Bachmann seems to lack a supply of parts and we are  the Beta  testers.    

Cheers,

Chuck N

PS I've been running my Accucraft K-27 for a number of  years without any significant problems.


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## chuck n (Jan 2, 2008)

Thanks to help from this thread and one over at Bachmann "Loose counterweights on K-27".   I now have my K back on the tracks and running.  I put in 0.008" shims as suggested by TOC.  If it weren't for all you helpful guys, I'd be getting more upset by the minute.  Thanks to Tommygunner who started the thead at Bachmann and Bob who started it here.  Special thanks go to Bill375 at Bachmann who suggested that shims were needed and TOC here who suggested going a little thicker on the shim.

I seriously doubt that I would have figured it out by myself.

One other thing.  Using the lid to the engine box to hold the upside down engine works great.  I'll have to try it with some of my other engines.

All's well that ends well, at least until the next problem.

Chuck N


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## folkestonekeith (Jan 17, 2008)

Reading the above I'm glad I did not buy one of the first run Bachmann K27 - learnt my lesson with the Bachmann Three-Truck Shay (dcc sound version) which shut down when the voltage exceeds 22volts - and I run MTS/Massoth at 24volts. 

Given that, I'm very happy with my Bachmann Two-Truck Shay and Heisler (both dcc'd and fitted with Phoenix Sound) - they sound just great winding their way up the garden!!) 

Keith


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## Curmudgeon (Jan 11, 2008)

Ah, but the second run was on the water before this "fix" was submitted to Bachmann. 
Maybe they caught it in time. 
There is one person who can tell us.


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## paintjockey (Jan 3, 2008)

Blackburn, if you don't have a use for that K-27 send it my way. I'll put it to work!!


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## jlyans (Jan 2, 2008)

To those of you who have fixed the loose counterweights, a question.  Where did you get your .007 or .008 shim material? Thanks. John


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## bobgrosh (Jan 2, 2008)

I didn't.
Looked all over. Everyone was out

Got back home at 10:00 PM worn out from the driving.

Sat down, stared at the poor dead Kay and sipped on a can of Coke.

Then it hit me.

Couple hours later,  Kay is alive an rolling.

Coke cans are .004
Fold and then cut.


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## Steve Stockham (Jan 2, 2008)

Heh, that'd make a good Coke commercial! Seriously though, American ingenuity wins out in the end! I'm glad you were able to solve your problem!


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## jimtyp (Jan 2, 2008)

Great tip on the coke can! If I can find brass today I'm going to dig through the recycle tonight


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## jlyans (Jan 2, 2008)

Good tip. Thank you. 
John


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## markoles (Jan 2, 2008)

Bob,

Don't you just love it when a plan comes together? 

Mark


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## Curmudgeon (Jan 11, 2008)

You will go blind trying to fit two thicknesses of shim into that gap. 

I bought $41 worth of brass shimstock, in various sizes. 
I have found on several that #3 axle takes about a .006" shim, but careful smoothing of the VERY rough machining of the axle flat with a file makes .008" work.


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## bobgrosh (Jan 2, 2008)

You will go blind trying to fit two thicknesses of shim into that gap.


 


Yep, nearly did go blind on the first few till I worked out a method.


Not saying aluminum is the way to go. Wait and see how this holds up, I may have to do it over with brass, but at least it got me going.


What I did:
Cut out a BIG piece of the coke can. Fold it in half so  the red is on the outside Makes it easier to see.) Starting at the fold, make cuts with scissors at 90 degrees from fold. Cut strips the exact width of the flats on the shaft. (well, as close as you can.)


Each strip is a couple inches long and contains two thickness of can with a fold on one end to hold the strips together.


I inserted a strip, fold end first into the counterweight. Push the strip through the counterweight until a tiny bit of the red paint appears sticking out the back side of the counterweight. Positioned the counterweight on the end of the shaft and slide the counterweight until the shim is captured between the inside flat of the counterweight and the flat on the shaft. wiggle the counterweight  by tilting it back and forth while applying light pressure to push the counterweight onto the shaft. It  takes a bit of work. Helps if you hold the other counterweight and not be pushing against the loco side-frames or journals. Work it on slowly with firm pressure.


Once the counterweight is pretty much seated, use an x-acto knife to trim the two layers of the aluminum flush with the bottom of the outer hole. Install the washes and screw. Tighten firmly.

Disclaimer:
I am a novice. It seems to be working for me, but if at all possible follow TOC's advice. I used this method because I do not have ready access to brass shim stock. I will probably replace these shims with brass as soon as I can locate the proper materials. Use my method at your own risk. You can not go wrong by following TOC's instructions. So, you might be better off waiting until you find the brass shim stock or even waiting for Bachmann to provide replacement parts. (I wouldn't hold my breath).

B0B


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## Curmudgeon (Jan 11, 2008)

Did you see what's up on the Bachmann forum? 
Three weeks of work. 
They are going to provide shim kits free of charge. 
TOC


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## bobgrosh (Jan 2, 2008)

How long will these last without replacement counterweights/DesktopModules/NTForums/themes/mls/emoticons/sick.gif


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## Curmudgeon (Jan 11, 2008)

The reason I used .008" is it's tight. 
You don't give it room to "work", it will last. 

I've got more mechanical background than I'll ever need to keep toy trains running!


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## jlyans (Jan 2, 2008)

I don't think the vast majority of K-27 owners are going to want to fix this themselves. And though some are in denial, the problem will have to be fixed sooner rather than later.  I think that better fitting, replacement counterweights are by far the best solution.

John


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## Curmudgeon (Jan 11, 2008)

Not my call. 
I'm doing 5 of them right now. 
If we get how many folks to do 5 each......


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## StanleyAmes (Jan 3, 2008)

Dave

Thanks for developing the fix. 

My K27 did not have much of a play when I first got the locomotive and I incorrectly did not think there was a problem.

After plowing show and hauling long trains the counterweights got looser and the binding that others reported began to occur, This was most noticeable on rollers and less so on the track. But the problem grows the more the locomotive is used in heavy usage.

This is akin to trying to remove a nut with a mis adjusted wrench. over time you will round out the edges of the nut.

Thanks go to Dave spending the time to identify the problem and develop the fix and also thanks for Bachmann for understanding the issue and getting a fix developed so fast.

Stan 

www.tttrains.com/largescale


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## TonyWalsham (Jan 2, 2008)

Wow Stanley.

That is very kind of you.

In the MLS chat a few days ago you said there was no such problem as loose counterweights.
Two minutes later you told us all there you had known about the problem all along.

Now we hear:
My K27 did not have much of a play when I first got the locomotive and I incorrectly did not think there was a problem.

After plowing show and hauling long trains the counterweights got looser and the binding that others reported began to occur, This was most noticeable on rollers and less so on the track. But the problem grows the more the locomotive is used in heavy usage.


So which is it?  
You did know.  
Or you did not know?

Some enquiring minds would like to know.  /DesktopModules/NTForums/themes/mls/emoticons/crying.gif


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## Madman (Jan 5, 2008)

*My thoughts go out to all who have purchased a Bachmann K27. I have just been reading some of the posts in these forums about the problems and possible fixes, and for the life of me cannot understand how or why such a product could leave the manufacturer. Even if some the new owners of these locos are in denial, they should band together with all of the other recipients and protest to Bachmann by demanding a refund, or at least a substantial rebate.*


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## Steve Stockham (Jan 2, 2008)

It happens a lot more than you would think and to just about _every_ large scale manufacturer! Aristo has definitely had their problems to match Bachmann's performance and even the venerable LGB had problems. MTH, Accucraft, Berlyn.....all have had problems at one time or another introducing new items! Sometimes it's something that can be "fixed" (ala TOC) and sometimes it may require replacement (the original Shay's power trucks.) Either way, those of us that have pre-ordered these engines need to realize that there will probably be "bugs" to work out! Yes, it feels very much like a crap shoot at times but that's all part of it so it's really not fair to get angry and demand refunds! What _would _be nice is if the powers that be would learn from this so it doesn't happen again.


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## David Fletcher (Jan 2, 2008)

I've stayed silent in all this nonsense, but I do feel that while the 'patch' is relatively simple, Bachmann should really send out new couterweights and do it right. Next, despite this engine being more complex than previous offerings and has many new innovations, none of this has anything to do with keeping counterweights tight. Its a most basic rule and issue for QA that model trains work best when wheels dont slip out of quarter, its one thing you ensure is right. Manufactuers have been getting quartering right for decades (and some not- you wonder why some at A dont see that as being a problem too!). I'm amazed this was not noticed during inital tests before shipping. Further the problem is probably in the original CAD design of the parts in 3D before tooling was done. 

Anyway, I'll shim my baby, but what a joke franky. What a shame for such a widely anticipated model, for such a move in the right direction for Bachmann. This has spoiled all their well earned Kudos, it should have been a huge triumph for them, now all we hear about is loose cranks! Will there be a review in GR, or will that wait till the next run when the units are sorted out? 

I dont think this issue will slow sales in the end, but its a shame none the less. 

David.


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## Gary Armitstead (Jan 2, 2008)

David,

Thank you. You reinforced my point. I would assume that the factory that produced these models used a CAD system and that the axles and counter-balances would have been machined by numerical control machines. That's why there is NO EXCUSE for this mistake! Sloppy QC and checking of the prototypes before the approval to manufacture. It's really too bad that this was not checked. No matter how nice the model is otherwise, this kind of thing can really hurt a company's "trust factor" for it's customers. This is a glaring over-sight. Too bad./DesktopModules/NTForums/themes/mls/emoticons/sad.gif


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## David Fletcher (Jan 2, 2008)

Well I did the patch. The main axle (3rd one) only needed fixing on one side. All the rest needed fixing badly. 2nd axle is still loose on one side, so I'll need to find thicker stuff. Having done this, I doubt they'll change any tooling for the cranks, what they'll do is shave off less from the axle on future models so that the fit is tight. Hence existing models can only be fixed with the slithers unless axles get changed as well. The only long term concern I have is that if the flat side is made smaller, the lock wont be complete either, with only the flat side making contact along part of the flat area inside the crank casting, and with wear I can see it wearing untill the crank spins all the way round. Maybe they should look at putting a flat side to both sides, rather than a D shape. 

Anyway, not my area...loads of designs in the past have seen axles properly quartered..not rocket science even if the electronics in this unit is! 

Thanks TOC, good on ya mate. 
David.


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