Jump to content
 
  • entries
    171
  • comments
    1,469
  • views
    376,240

Silver Sidelines

5,519 views

Continuing my BR(NE) saga I have resurrected a couple of elderly Bachmann B1s that have been quietly slumbering in their boxes.

24728938247_3dc8619091_b.jpg
Bachmann B1s – Widlebeeste and Hartebeeste

There is an issue with these particular early models and mine were not immune! For whatever reason the black plastic wheel centres expand with time and catch on the coupling rods preventing the wheels from freely turning. The affliction does not affect the centre driving wheel and rather puzzlingly it is the rear pair of driving wheels that is most at risk. Fellow modellers report that Bachmann BR standard 4MT models of a similar vintage are also affected.
24728946137_04705733e2_b.jpg
Bulging rear wheel centre

Another view of the problem.
37751213305_0d02734686_b.jpg
Bulging Plastic

The wheel centre appears to be a type of nylon and can be poked out from behind the wheel using a cocktail stick or very small screw driver. I think it is a push fit into the wheel casting but I cannot be sure.

25726297978_825730468b_b.jpg
Bachmann B1 rear wheel set

I guess it is possible to remove the wheel centre whilst leaving the wheel set on the engine. However I think it makes life a whole lot simpler to unbolt the connecting rods and lift out the complete wheel set.

27819606779_56671faaf4_b.jpg
Bachmann B1 plastic wheel centre

The outside edge of the plastic inlay can then be carefully rubbed with 400 grade wet and dry (emery) paper, at the same time gently massaging the spokes back into a flat shape (a bit of warmth seems to help). The ‘nylon’ is tough and it is a slow process to reduce the diameter such that the plastic centre is a snug fit into the cast metal wheel. I have repaired two models and have not used any adhesives to hold the resized wheel centres back in place.

There is a short video here comparing before and after running:

http://youtu.be/BaXy6XUSMoA

Comments from fellow modellers suggest that the wheel centres will continue to expand with time. I have no knowledge of the type of plastic or the chemical mechanism that is causing the expansion, but given that the models are now at least 25 years old I am not expecting a huge increase in expansion over the next couple, or even the next five or more years. We shall have to wait and see!

39597270661_b1d61a0dfe_b.jpg
Bachmann A4 Split Axles

The other issue with these old ‘split chassis’ models is the fragile state of the nylon axles. Bachmann refer to the axles as ‘isolators’. They are a force fit onto the ‘squared’ wheel stubs and over time they will crack and break even without any use.

http://youtu.be/YWP0htE-4qM

EBay has lots of listings where old Bachmann models are offered ‘for sale’ – tested working, where subsequently it is obvious that the nylon ‘isolators’ have failed. Even in their broken state the bits of nylon will offer sufficient grip to propel the mechanism backwards and forwards in a straight line. It is only when the wheels are subjected to side forces such as when negotiating a long curve that the wheels will be forced apart – revealing the true nature of the problem.

39348112671_54a43001e1_b.jpg
Insulators and Circlips courtesy of Bachmann

Salvation is at hand and sets of isolators are available to purchase direct from Bachmann Technical Department in Leicester.

 

Thank you for your recent e-mail, we can supply a set of axle isolators (2 plain & 1 geared) for £3.00 and 4 circlips for £1.00 plus £2.00 p&p. The isolators may have different tolerances due to the wear on the tooling. If they are a little slack our technicians use a small amount of glue to keep them in place. If you wish to order please contact us on 01455 245 575 to pay via card, alternatively please send a cheque/postal made payable to Bachmann Europe with your order details, name and address. Please quote SD##### on all correspondence, offices are open 8.30am until 5pm.


Why buy ‘circlips’ you ask? In order to replace the ‘isolators’ I find it best to remove the whole wheel set from the model. On Bachmann split chassis locomotives the valve gear and connecting rods are held by a circlip which slots into a groove on the end of the middle axle. Prising the circlip out of the groove with a pin or fine screw driver allows the valve gear to be disconnected, the connecting rods lifted off and the coupled wheel set lifted out from the chassis. The only problem being that the circlips are very ‘springy’ and if they haven’t shot off the model whilst being first removed, they are likely to disappear out of sight whilst being replaced. Life is too short to spend time searching for missing circlips – you just need a supply of replacements!

39596529401_dc150de4ba_b.jpg
Bachmann B1 – spot the circlip

My experience over a number of years is that the ‘standard’ isolators fit the majority of Bachmann’s split chassis models. One exception is the old Bachmann J72, where the centre gear wheel is offset.

39568223762_0ab2f4fd3f_b.jpg
Bachmann J72 Split axles – from an advertisement on eBay

I have not tried to source isolators from Bachmann for the J72 but I have seen 3D printed copies offered ‘for sale’ on eBay. Bachmann isolators are ‘nylon’. I am guessing that 3D printed isolators will not be nylon and may have different mechanical properties.

24728941477_3bc8a2bdc8_b.jpg
Bachmann B1 – disconnected valve gear

Handling elderly models can be quite stressful! Bits just break and ping off – almost without touching! On one of my B1s the plastic motion brackets supporting the valve gear just fell off the mazak chassis casting. Luckily this is an easy repair - use a drop of Wilkinson’s super glue and push back into place.

http://youtu.be/MKVoG1SsIOI

The proof of the pudding is in the eating, and I now have two nice smooth running models.

39601972511_f0017ebcc8_b.jpg
Two Elderly Sisters

For the moment I have two good runners which can be bought for a fraction of the price of the latest offerings from Hornby, Bachmann and Dapol – food for thought?

30400631912_a6ee43e601_b.jpg
A proper wheel centre - (19thC?) un distorted cast iron, from out of our garden
  • Like 3
  • Informative/Useful 1

32 Comments


Recommended Comments



It is the new DCC ready chassis.  BC (Before Covid) by watching around i was able to pick up several B1s with then new chassis fairly cheaply, pounds 50 to 60.  Several had had their body badly weathered and I suspect some came from individuals who had gone for the Hornby B1 which, I have to admit, is a better model.  However,  I had the Bachmann bodies and the new chassis was a lot cheaper than building one.

 

Link to comment
8 minutes ago, Theakerr said:

It is the new DCC ready chassis. 

 

 

Thank you Theakerr for the clarification.  I recently 'won' a couple of  A Harold Bibbey.  I managed to get £85 for the surplus one.

 

Cheers Ray

 

 

Link to comment
On 07/08/2020 at 15:40, John Tomlinson said:

Glad it's worked out for you - the next one will be a breeze!

 

John.

 

Hello John

 

I don't know what I was doing when all these comment came in.  Monday today - we have had sunshine and rain.  Long may it last.

 

Cheers Ray

  • Friendly/supportive 1
Link to comment

For me, I generally try to purchase 'preserved kettles', hence why it had to be Mayflower.

 

The body does have it's flaws, and I have been wondering whether the older bodies will fit the non-split chassis newer ones.

 

Still, this seems to be working now, so job's nearly a gud'un.

 

Al.

  • Informative/Useful 1
Link to comment

Atom, see above.  It is a perfect drop in fit.  Only issue is the new chassis is lighter than the old one and depending on your needs you may need to add extra weight.

  • Like 1
Link to comment
On 10/08/2020 at 23:18, atom3624 said:

... I have been wondering whether the older bodies will fit the non-split chassis newer ones.

 

 

Hello Atom I see you have your answer from Theakerr.  I am guessing you might need to change the colour of the wheel spokes?

 

Some of my split chassis models run really very well.  A bit of a lottery.  Digressing - but not all newer Bachmann chassis run smoothly.

 

Thank you all for keeping the thread alive.

 

Cheers Ray

Link to comment

Hi Ray, I've some superb newer ones - A1 and A2 for example, and some not so, as you say.

 

Agreed, also, I've one superb LNER Green Arrow - drivers look like it's probably an old-type split chassis but it's a superb runner - 'limited edition' or not, they get run in my house!

 

Totally agreed, it's a bit of a lottery, I'm just more wary of the fragile 'axles' of the split chassis now.

 

Al.

  • Like 1
Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...