Hornby Class 50 worm drive issue. Solved.

[Enterprisingwestern]

 

I have read the other topics on the forum dealing with this issue, but none seem to have exactly the same problem.

I have retrieved a couple of the above locos out of storage, and, like others have found, they were very slow runners.

Dismantling the loco and investigating I found the motor spins freely, as do the axles when the cap is taken off the top of the gear tower and the worm drive is removed.

So, going on the experiences of others on the forum, I gave the worm gear and the housing a good clean, oiled them with EMGS clock oil, (which I normally use), clicked it all back together, and voila, still as stiff as before.

I removed the clip on retaining cap, and on spinning the cardan shaft all seemed free, replacing the cap stiffened it all back up again considerably, despite the copious lubrication.

So my question is this, is it possible that the cap has shrunk/distorted enough to tighten the worm gear in its bearing, and has anybody encountered this problem, if so how did you solve it?

My initial thought is to file, (with fine emery paper around a drill of suitable diameter), the four bearing services to give the worm a tad more wriggle room.

 

TIA.

Mike.

Edited December 27, 2021 by Enterprisingwestern

[adb968008]

25 minutes ago, Enterprisingwestern said:

 

I have read the other topics on the forum dealing with this issue, but none seem to have exactly the same problem.

I have retrieved a couple of the above locos out of storage, and, like others have found, they were very slow runners.

Dismantling the loco and investigating I found the motor spins freely, as do the axles when the cap is taken off the top of the gear tower and the worm drive is removed.

So, going on the experiences of others on the forum, I gave the worm gear and the housing a good clean, oiled them with EMGS clock oil, (which I normally use), clicked it all back together, and voila, still as stiff as before.

I removed the clip on retaining cap, and on spinning the cardan shaft all seemed free, replacing the cap stiffened it all back up again considerably, despite the copious lubrication.

So my question is this, is it possible that the cap has shrunk/distorted enough to tighten the worm gear in its bearing, and has anybody encountered this problem, if so how did you solve it?

My initial thought is to file, (with fine emery paper around a drill of suitable diameter), the four bearing services to give the worm a tad more wriggle room.

 

TIA.

Mike.

Check the motor is mounted evenly.

 

i had one exactly the same, take the motor out, sweet as a bird. Cleared both gear boxes, turned fine.

reassembled it, went like a dog.

Went around a lot of circles here, taking the drive shaft off one side, then the other, disconnected the fan drive, bench tested the motor.. every-time everything was fine.
reconnected.. back to a dog.

 

Turned out the drive shaft from loco to gear towers was tense on one side, slightly more slack on the other.. tense side was locking it up.

slight reposition of the motor everything was fine, it was only a mm at most, but was enough to unbalance it. Discovered by accident twanging the shaft, and saw one side was tense, the other vibrated slightly.

unlike other drive shaft locos the shaft push fits, which gives the tension, most others just slide fit giving that micro amount of wiggle room.

once balanced it was fine and I had a celebratory drink as it took hours.

 

no guarentees, but it solved mine, 50035 was the patient.

Edited December 27, 2021 by adb968008

[Enterprisingwestern]

8 minutes ago, adb968008 said:

Check the motor is mounted evenly.

 

i had one exactly the same, take the motor out, sweet as a bird. Cleared both gear boxes, turned fine.

reassembled it, went like a dog.

Went around a lot of circles here, taking the drive shaft off one side, then the other, disconnected the fan drive, bench tested the motor.. every-time everything was fine.
reconnected.. back to a dog.

 

Turned out the drive shaft from loco to gear towers was tense on one side, slightly more slack on the other.. tense side was locking it up.

slight reposition of the motor everything was fine, it was only a mm at most, but was enough to unbalance it. Discovered by accident twanging the shaft, and saw one side was tense, the other vibrated slightly.

unlike other drive shaft locos the shaft push fits, which gives the tension, most others just slide fit giving that micro amount of wiggle room.

once balanced it was fine and I had a celebratory drink as it took hours.

 

no guarentees, but it solved mine, 50035 was the patient.

 

Thanks for your input.

I should maybe have mentioned that I've disconnected and removed the entire bogie and cardan shaft, and that my tests are being done with the unit in my hands.

 

Mike.

[Enterprisingwestern]

 

Problem solved.

I have given the gear towers another coat of looking at.

It would seem that, in my ignorance, the worm has a bearing at each end and they were stuck solid to the worm shaft, therefore causing the cardan shaft to have to turn the bearings as well as the worm in its plastic mounts.

Dismantling the worm shaft further and removing the bearings, cleaning it all up and reassembling so that the shaft rotates in the bearings as designed has solved the problem.

A simple answer at the end of the day, an understanding of the mechanics of the gear tower would have made this blindingly obvious in the first place, I can only blame excess christmas pudding in my eyes!

 

Mike.

[MIB44]

Thanks Mike, your post helped me to fix my own Hornby Class 50 after nearly two weeks of working on it and much head scratching!!

 

Mine was bought back in Dec 2011 and is the factory sound fitted 50 037. I only had a small shelf layout at the time so it had a bit of light running back & forth and then went in to the cupboard. Wind forward 11 years and I've taken early retirement and finally started to build my long promised layout in the box room.

 

I got the Class 50 out for a test run but found it to be very stiff & slow, in fact hardly moved at all. Plenty of Peco ElectroLube later it was at least now moving, but still very slowly! I read several forum posts and worried that it was the PCB issue mentioned and was about to start the search for a replacement but thought I'd have one more look through RMweb and came across your post.

 

I've stripped the first worm gear out of the tower and low & behold found that one of the two bearings is completely immovable!! No amount twisting with a variety of tools will free it, however I re-assembled it with plenty of lubrication on the plastic cup it sits in and re-attached the top cover. Back on the track and problem solved!! Now running very smoothly and fast! 👍😀

 

Thanks again...

[c3nf]

Many thanks to all the above. Having purchased and test run R2348 Resolution many years ago and then put it in a display cabinet, I retrieved it at the request of my grandson and found it refused to run. The lights came on but the motor hummed without turning. I contacted Hornby but they would not look at it as they said it was too old (not impressed by that!). Eventually stripped it down myself and found one of the worm bearings was seized and unmoveable. Cleaned, lubricated and re-assembled and now running quietly and smoothly. Only remaining problem was that only the red lights lit up. Eventually located the cause of this problem - R2348 was one of the models not fitted with a white bulb!

Edited July 9, 2024 by c3nf

[dugdug03]

It's also worth checking the gears in the bogie frame as it highly likely the same lubricants was applied and i have in my own experience had these seize along side the bearings and worm drives.

[andyman7]

I've found that this is quite a frequent occurrence with Hornby locos that haven't been used for a very long period. I'm quite used to the strip/clean/relubricate process when recommissioning items!

[Enterprisingwestern]

14 hours ago, andyman7 said:

I've found that this is quite a frequent occurrence with Hornby locos that haven't been used for a very long period. I'm quite used to the strip/clean/relubricate process when recommissioning items!

 

This could be the reasoning behind manufacturers putting a pound and a half of grease in the bogies and gear towers?

 

Mike.

[andyman7]

5 hours ago, Enterprisingwestern said:

 

This could be the reasoning behind manufacturers putting a pound and a half of grease in the bogies and gear towers?

 

Mike.

I'm not sure but to be honest, if a mechanism has lain unused for a number of years I don't expect it to necessarily work without some attention - often they do, but oxidisation and dried lubricant are always risks