Hornby Class 43 drive seized one end

[fiftyfour fiftyfour]

One of my Hornby HST power cars (circa 2008, the then "new" version, R2704 pack) has decided that after being last operated about four years ago without a problem it wants to play up. It initially crawled along at a very slow pace with only one bogie moving, and bench testing showed the mechanism between the cogs and the carden shaft at the No1 end (cab end) had seized so the good end was fighting against a static end. Stripped it down and built it back up one bit at a time, and its either the housing around the brass thing which I'm going to call a worm drive, or the worm drive locking up against the cogs. Anyone any ideas on a permanent fix please? For now I'm running it without the carden shaft and the brass worm drive so it's only powering one bogie, which seems to have negligible effect on performance but it doesn't feel like that is a long term fix!

 

[125_driver]

57 minutes ago, fiftyfour fiftyfour said:

One of my Hornby HST power cars (circa 2008, the then "new" version, R2704 pack) has decided that after being last operated about four years ago without a problem it wants to play up. It initially crawled along at a very slow pace with only one bogie moving, and bench testing showed the mechanism between the cogs and the carden shaft at the No1 end (cab end) had seized so the good end was fighting against a static end. Stripped it down and built it back up one bit at a time, and its either the housing around the brass thing which I'm going to call a worm drive, or the worm drive locking up against the cogs. Anyone any ideas on a permanent fix please? For now I'm running it without the carden shaft and the brass worm drive so it's only powering one bogie, which seems to have negligible effect on performance but it doesn't feel like that is a long term fix!

 

Can't really help, but I have been running a power car for several years with exactly what you describe (ie only one bogie powered), and I've found it to perform equally as well, and in some ways better than other power cars in the fleet. Its not had a problem in about 4 years of running that way, and has probably done well over 20 hours running in this state.

[33C]

If it is fitted with thrust washers, these can seize on the shaft if kept in less than dry conditions. Remove, grease, replace.

[34theletterbetweenB&D]

If one worm gear isn't turning but the other worm gear is, the most common problem cause is one of the plastic drive couplers slipping, within the flywheel, or on the worm shaft. A little superglue rectifies.

 

1 hour ago, 125_driver said:

...have been running a power car for several years with exactly what you describe (ie only one bogie powered), and I've found it to perform equally as well, and in some ways better than other power cars in the fleet. Its not had a problem in about 4 years of running that way, and has probably done well over 20 hours running in this state.

These centre motor drives typically have ample traction with both bogies driven to race along with 30 to 40 carriages.  The Bachmann drive in their BR DMU's such as the class 105 and 108 are of the centre motor type but with only one bogie driven and will haul over a dozen carriages, so a small train of HST carriages is not going to be a problem.

[fiftyfour fiftyfour]

1 hour ago, 34theletterbetweenB&D said:

If one worm gear isn't turning but the other worm gear is, the most common problem cause is one of the plastic drive couplers slipping, within the flywheel, or on the worm shaft. A little superglue rectifies.

 

These centre motor drives typically have ample traction with both bogies driven to race along with 30 to 40 carriages.  The Bachmann drive in their BR DMU's such as the class 105 and 108 are of the centre motor type but with only one bogie driven and will haul over a dozen carriages, so a small train of HST carriages is not going to be a problem.

And more recently (its been a week long stock healthcheck) I found a very nearly identical issue on a Dapol Class 121, it got warm and then the plastic drive couplers started slipping on the rod and once they started slipping the train (load: one vehicle) came to a stand. I dismantled whilst heavily cursing the "new" stuff vs the Lima stuff which just works out of the box, cleaned up and its better but still not brilliant- I was reluctant to apply glue on a tiny drive shaft but it might come to that if there is a repeat.

 

Back on the HST power car I did think there may be some dirt in the cogs as initially they didn't feel free running, but a little bit of gentle working got them moving. I'm now thinking its the worm shaft housing has contracted with age as its as if something is clamping the worm shaft. I don't know what the thrust washers look like, I don't think is has them unless they are the bits the worm drive sits in?

 

[34theletterbetweenB&D]

1 hour ago, fiftyfour fiftyfour said:

Back on the HST power car I did think there may be some dirt in the cogs as initially they didn't feel free running, but a little bit of gentle working got them moving. I'm now thinking its the worm shaft housing has contracted with age as its as if something is clamping the worm shaft. I don't know what the thrust washers look like, I don't think is has them unless they are the bits the worm drive sits in?

In this drive arrangement, because both worms are driven from a common motor shaft, if one worm is not rotating but the other bogie runs as you describe, something is either slipping in the drive line to the stationary worm, or a component such as the cardan shaft is disengaged or broken.

 

[fiftyfour fiftyfour]

1 hour ago, 34theletterbetweenB&D said:

In this drive arrangement, because both worms are driven from a common motor shaft, if one worm is not rotating but the other bogie runs as you describe, something is either slipping in the drive line to the stationary worm, or a component such as the cardan shaft is disengaged or broken.

 

Carden shaft spins when its disconnected from the worm, but it's impossible to see what is happening between the shaft end and the worm once the cover goes back over. 

[Marcyg]

On 05/04/2024 at 22:31, fiftyfour fiftyfour said:

Carden shaft spins when its disconnected from the worm, but it's impossible to see what is happening between the shaft end and the worm once the cover goes back over. 

Hornby grease is known for going hard after a period of time. It could have jammed that gearbox up and is causing the shaft to spin on the worm gear. A full strip down, clean and lubricate should work. The drive cup on the worm may need gluing as it could have split it

[fiftyfour fiftyfour]

39 minutes ago, Marcyg said:

Hornby grease is known for going hard after a period of time. It could have jammed that gearbox up and is causing the shaft to spin on the worm gear. A full strip down, clean and lubricate should work. The drive cup on the worm may need gluing as it could have split it

The worm gear isn't spinning, the carden shaft spins freely from the motor end and when I separate the parts and try manually turning the worm drive with the carden shaft between my fingers it doesn't budge

[Neil]

My guess is that whatever lubrication was used in the worm drive housing has set solid. I've had this problem a couple of times with (China built) Hornby steam locos that I've repaired for a friend. In the case of the steamers it was the brass axle bearings setting solid on the axles. Peco power-lube is your friend, apply plenty, work into the seized area as best as possible; once freed up, clean up the excess.