Bachmann BR Class 4 woes

[KeithMacdonald]

Just bought this Bachmann 4-6-0 Class 4 Standard Loco.

 

 

It appears to be in good condition, and does run. Except it moves with a strange waddling motion, bit like a duck! It's most noticable when looking at it from in front, and the body oscillates from side to side, in time with the rotation of the connecting rods.

 

Has anyone else had similar experiences? I'm guessing one (or more) of the cranks is out of alignment, but how to tell which, what or where? Or how to fix it?

 

Thanks!

[Butler Henderson]

Its a split chassis model so its possibility suffering from a breaking rather than fully broken axle. Undo the plastic retaining plate on the underside and check the axles to see if the plastic centre part of one is split or splitting Bachmann may still have spare plastic parts https://www.Bachmann.co.uk/service-request/  or you can buy them from Peters Spares  https://www.petersspares.com/peters-spares-ps30-Bachmann-replacement-axle-set-jubilee-scot-4mt-manor.ir subject to them being the correct type.

Edited January 7, 2020 by Butler Henderson

[PJT]

Even though it's a split chassis loco, I'll bet it's not a wheel/crank quartering problem.  There's another very common fault with these locos - the plastic insert in one or more of the driving wheels has swollen and distorted to the point where it's catching a coupling rod, most likely, if you have a look at the driving wheels.  To fix the problem, try the following:

 

Remove the insert (it just gently levers out, after undoing the coupling rod from the wheel, leaving the die cast metal wheel behind). 

Then straighten out the distortion with your fingers, using a bit of warmth (e.g. put the insert in a cup of hot water for a minute or so). 

Using fine wet and dry paper remove sufficient of the diameter of the 'rim' of the swollen insert to get it back to the right size - it should fit without any force back into the metal wheel casting. 

When fitting it in for good and before replacing the coupling rod, use a small dab of glue on the back of the insert to hold it in place - you don't want it coming loose and fouling the coupling rod. 

 

That should cure it (I've done dozens of exactly this repair on both Bachmann Std Class 4s and Bachmann B1s with split chassis).  It restores smooth running like magic.  Good luck!

 

Pete T.

 

[PJT]

2 hours ago, Butler Henderson said:

Its a split chassis model so its possibility suffering from a breaking rather than fully broken axle.

 

Sorry, Butler Henderson, you must have posted your comment a few seconds before I posted mine.  Mine reads as though I read your post and then contradicted it in a bit of a high handed manner, whereas actually I didn't see yours at all before I posted mine.  Apologies if you read mine that way and I assure you my answer would have been phrased a bit differently if I'd seen yours first!

 

Pete T.

 

[Fireline]

I've got one of these in the "to do" box. Wheels are like non-EU regulation bananas!

Edited January 8, 2020 by Fireline

[andyman7]

Thanks, ditto, just bought one 'needing attention' (cheap and sold-as-seen) and first thing I noticed was that the wheel centres were swollen/distorted.....

[KeithMacdonald]

On 08/01/2020 at 12:37, Fireline said:

I've got one of these in the "to do" box. Wheels are like non-EU regulation bananas!

 

1 hour ago, andyman7 said:

Thanks, ditto, just bought one 'needing attention' (cheap and sold-as-seen) and first thing I noticed was that the wheel centres were swollen/distorted.....

 

Have you been able to fix them?

[andyman7]

It's in the pile to deal with but at least I have the guidance in this thread from people who have been there before

[PJT]

On 25/01/2020 at 19:11, KeithMacdonald said:

Have you been able to fix them?

 

On 25/01/2020 at 19:48, andyman7 said:

It's in the pile to deal with but at least I have the guidance in this thread from people who have been there before

 

For your info, if you're going to have a go at the plastic wheel centres for the first time, I've just put a hopefully useful post about the crank pins on the centre driving wheels on these locos on the thread 'Which size nut spinner for Bachmann valve gear?'

 

Pete T.

 

[TonyMay]

A little bit of waddling is prototypical from a 2-cylinder engine.  

[andyman7]

The class 4MT has been sorted, thanks to PJT for the advice on how to go about this. I managed to avoid losing the little circlips on this one, the centre crankpin does have to be eased out to get the connecting rods off and the plastic wheel inserts out. A little boiling water and they were all flat, in the end I used fine scissors and a scalpel blade to reduce the circumference so that they lay flat in the wheel, secured with a little Loctite.

 

The next project is a B1, this is a Bachmann one but the chassis has been swapped for a Replica one with the old Ringfield motor and traction tyres. The axles are fine but it again has swollen wheel inserts. However, the connecting rods do not have hex nuts, it looks like they are force fitted pins but any confirmation would help. I have got the rest of the motion off but this time both circlips pinged off into the ether so it looks like I will need to try and get some from Bachmann.

[34theletterbetweenB&D]

1 hour ago, andyman7 said:

... the connecting rods do not have hex nuts, it looks like they are force fitted pins but any confirmation would help...

They are.

[roythebus]

Sometimes the waddling may be caused by too much sideways paly in the driving axles. Maybe fit spacer washers to the leading and trailing drive axles to reduce side slop.

[No Decorum]

14 hours ago, andyman7 said:

The class 4MT has been sorted, thanks to PJT for the advice on how to go about this. I managed to avoid losing the little circlips on this one, the centre crankpin does have to be eased out to get the connecting rods off and the plastic wheel inserts out. A little boiling water and they were all flat, in the end I used fine scissors and a scalpel blade to reduce the circumference so that they lay flat in the wheel, secured with a little Loctite.

 

The next project is a B1, this is a Bachmann one but the chassis has been swapped for a Replica one with the old Ringfield motor and traction tyres. The axles are fine but it again has swollen wheel inserts. However, the connecting rods do not have hex nuts, it looks like they are force fitted pins but any confirmation would help. I have got the rest of the motion off but this time both circlips pinged off into the ether so it looks like I will need to try and get some from Bachmann.

I have a couple of Replica ones. Why they have traction tyres has always puzzled me. The loco is extremely heavy and has no need of them. The Mainline models earlier than the Replicas didn’t have them, nor did the later Bachmann models.