Worn Bachmann Class 25 Mechanism Refurbishment

[Grizz]

Gradually some of the Bachmann class 25s in my collection have been failing. For me this is sad and somewhat irritating, considering I have always taken good care of them, with regular checks and lubrication. After a fourth loco dropped by the wayside recently I decided to take the plunge and investigate further. 

 

I have quite a large collection of the various classes that Bachmann have produce over the years, including some of the very first examples of classes 20, 24, 25, 37 and 66s. Quite a few of these were bought in batches of the same loco at the same time and altered and re numbered  to create a bigger fleet. Following an obsessively identical program of running each loco in, when new, they settled down to general running. After a while a few examples began to display a particular noise when the power was rapidly shut off, which is best described as a chatter. To try to resolve this I applied new grease and lubrication as best as I could. This did quiet down the chatter for a while but it soon re-emerged and gradually worsened. It should be said a no point were there any squeaking sounds, but a low growling did come from one class 20. In total I would say that this chattering has affected 20 or so locos to a greater or lesser degree and is particularly prevalent in class 25s. 

 

Last week two of the affected class 25s finally stopped working altogether. Today I stripped down the two of them and found evidence of metal dust from the bearings. 

 

 

 

This condition is despite plenty of lubrication. To make matters worse, replacement bearings are not a standard stock spares item for Bachmann, despite being easy to fit and lubricate, so I have had to rob two replacements from the other failed loco, making one good one out of the two....for now. 

 

Does anyone one know of a suitable replacement or 'after sales' bearing that would do the job? I have no idea the work involved in producing one or what the costs might be, but I would have thought that someone on RMWEB would have some experience in this area. 

 

 

metal dust is not a good sign but there is nothing wrong with the motors and nothing wrong with the gear chain or shafts. So difficult to justify buying two whole replacement bogies for just these two locos. I have not begun to dismantle the rest of the similarly affect locos yet as I can't quite summon the courage to face it.

 

This is is not a pretty sight but can't be that uncommon...????

 

 

any my thoughts or similar experiences??? 

 

Cheers all.

 

Grizz

Edited October 9, 2019 by Grizz
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[Fat Controller]

Some dimensions might be of use; bore, outside diameter, and length of bearing, and perhaps a close-up photo of one, both in-situ and removed from the loco.. 

[34theletterbetweenB&D]

One observation I would make is that unless you have cleaned off the brass filings from one end of the plastic underside moulding, there has clearly been gross wear one end, much less (negligible) the other end.

 

I don't have the numbers you do but have well used 20s and 24/25, not seen any evidence of significant wear. All greased on the bogies with either salvaged excess original grease, or Woodland Scenics grease.

 

If those brass filings are worn from the axle bearing collars, my suspicion would be a poorly machined axle surface. I feel you will need to replace the bogie complete at the seriously worn end, because those filings will be throughout the gear tower, stuck in the grease. There are no filings to speak off in the moulding that covers the axle gear at the outside end, yet the surrounding horizontal surfaces are well coated with filings. The filings that would have got into the axle cover area will be mainly on the gear faces.

[Grizz]

Sorry for the delay in replying Fat Controller, flipping digital calipers are playing up a touch. 

 

Right here goes.....unless someone else has nuclear calipers. 

 

 

 

 

 

think i think I might have a suspect for the chattering. Not sure if you see the difference between the two photos in relation to the position of the worm drive. There is about 0.5ish mm longitudinal play in the position. This is not apparent on all the bogies, although irritatingly I have temporarily lost two of the bearings.....somewhere, so I only have two bogies to compare. 

 

 

 

Sorry for the quality of the photos. 

[Grizz]

1 hour ago, 34theletterbetweenB&D said:

One observation I would make is that unless you have cleaned off the brass filings from one end of the plastic underside moulding, there has clearly been gross wear one end, much less (negligible) the other end.

 

I don't have the numbers you do but have well used 20s and 24/25, not seen any evidence of significant wear. All greased on the bogies with either salvaged excess original grease, or Woodland Scenics grease.

 

If those brass filings are worn from the axle bearing collars, my suspicion would be a poorly machined axle surface. I feel you will need to replace the bogie complete at the seriously worn end, because those filings will be throughout the gear tower, stuck in the grease. There are no filings to speak off in the moulding that covers the axle gear at the outside end, yet the surrounding horizontal surfaces are well coated with filings. The filings that would have got into the axle cover area will be mainly on the gear faces.

 

34theletterbetweenB&D, well spotted. Upon closer inspection there is significant wear between the brass bearing end and brass worm drive end where the faces meet. As can be see from the polished surfaces in the previous photos.  This is directly adjacent to the front wheel set at each end. As you say the grease is smothered in it and the nylon gears have traces of it on them.

Note to self, when lubricating these locos in future I will have to drop the bogies out of the chassis to ensure the grease gets between the bearing and worm drive. 

 

One of the locos concerned was numbered 25087. Another was 25279.

[RobjUK]

How about these, with a slice of 3mm ID /  4mm OD brass tube soldered on bring the outside up to size?

https://www.ebay.co.uk/itm/12-turned-brass-loco-axle-bushes-bearings-mainframe-bushes-for-2mm-axles/113776789959?hash=item1a7da009c7:g:1vQAAOSwECNc~Ng1

 

The same place has 2mm shim washers:

https://www.ebay.co.uk/itm/24-turned-brass-loco-axle-spacing-shim-washers-for-2mm-dia-axles-0-25mm-thick/112005964022?hash=item1a141360f6:g:TG4AAOSwzgRWzEZY

 

[Grizz]

RobjUK, many thanks for the idea and suggestions. Spot on. I've built one complete bearing and have a second close to completion. 

 

I bought both the products you suggested and oddly I already had a length of 4mm brass tube. The thin flange was knocked up from an off cut of brass sheet.

 

The photo below is progress so far. 

 

 

Hopefully I can test run the loco with just the one bogie assembled with the new bearings and the other 'trailing' with the worm removed. That way any wrinkles can be ironed out. 

[RobjUK]

They look promising, I hope everything works OK!

 

[Martin 1960]

just found this forum, very useful thanks! I also have a 25 279 which I bought new years ago. It's always been a stalwart on my layout and I run it in preference to any of my Lima 33s even towing an unmotored Hornby 25 +7 coaches behind it for the full Cambrian Coast Express. Just run it for the first time in a few months and it's very sluggish and noisy. All the wheels turn under power. Took it to bits and found a small amount of brass filings on each bogie. Test ran it off the track no problem but it stalls after about 5 mins on the track. Ran the motor without bogies connected all looked fine. Finally isolated what I thought was the errant bogie and the other one ran off the track quite happily for over an hour. I've ordered a new bogie from eBay hopefully this will resolve it!