Replacing gears on LGB Loco

viaEstrecha

viaEstrecha

Spanish metre gauge in G scale (on the cheap)
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Until now, I've managed to avoid having to mess about with the drive train on any of my locos. Unfortunately, I need to replace the reducing gears in my imported second hand LGB Corpet-Louvet (LGB 21780), they having stripped when it derailed in a hidden part of the line but somehow managed to keep running for several minutes. I have obtained the replacement set of gears (LGB part E133761).

I haven't a clue where to start. I can see from the exploded diagram how to access the wheelset, but am scared stiff of a. disengaging the coupling rod (is it held on with some push-on/pull-off pin shaped like a hexagonal nut? Do I use pliers or is it actually threaded?) and b. subsequently taking a wheel off the axle in order to fit the new gears (does the axle tap simply out of the wheel with a punch?).

Anyone have any helpful hints or tips to give me some confidence, please?
 
viaEstrecha said:
Until now, I've managed to avoid having to mess about with the drive train on any of my locos. Unfortunately, I need to replace the reducing gears in my imported second hand LGB Corpet-Louvet (LGB 21780), they having stripped when it derailed in a hidden part of the line but somehow managed to keep running for several minutes. I have obtained the replacement set of gears (LGB part E133761).

I haven't a clue where to start. I can see from the exploded diagram how to access the wheelset, but am scared stiff of a. disengaging the coupling rod (is it held on with some push-on/pull-off pin shaped like a hexagonal nut? Do I use pliers or is it actually threaded?) and b. subsequently taking a wheel off the axle in order to fit the new gears (does the axle tap simply out of the wheel with a punch?).

Anyone have any helpful hints or tips to give me some confidence, please?
Click to expand...
As a rule there is a hexagonal nut on the coupling rod that is best gently removed with a spinning spanner, the LGB Tool set has the right sized one. I have the right tools. Just the other day they were used to pull apart an LGB loco to repair it. if you are scared you are always welcome over here to do the job with the correct tool.
 
dunnyrail said:
As a rule there is a hexagonal nut on the coupling rod that is best gently removed with a spinning spanner, the LGB Tool set has the right sized one. I have the right tools. Just the other day they were used to pull apart an LGB loco to repair it. if you are scared you are always welcome over here to do the job with the correct tool.
Click to expand...
Once again to my rescue! That would be great, thanks, John - so much better to do it the first time with the right tools and under supervision of an adult! :D
I'll be in touch to arrange a flying visit when you're free,
 
viaEstrecha said:
Once again to my rescue! That would be great, thanks, John - so much better to do it the first time with the right tools and under supervision of an adult! :D
I'll be in touch to arrange a flying visit when you're free,
Click to expand...
Conversation sent.
 
Hi Martyn,

The part you have ordered, E133761, is the intermediate gear in the motor block. This is part No. 103 on the exploded diagram I'm looking at. You do not need to remove any wheels from axles to replace these. These gears spin freely on metal shafts, part No. 102, that clip into the motor block. I assume you have removed the bottom motor block cover to check the gears and that the drive gears on the wheelsets are still OK. Usually the worms on the motor shaft chew up the worm gear half of the intermediate gear and the drive gears on the wheel axles are still good. There could also be a mis-match between the spur gear half of the intermediate gear that has caused the failure. This shows where the mis-match I'm speaking of occurs: LGB 20450 and brethren drive gear issue. In this situation the axle drive gear(s) may need replacing. Hopefully not, but they may need some sideway adjustment on the wheel axle or adding some washers to the intermediate gear shaft as suggested by Dan to get a better gear mesh.

I do not have a LGB Corpet-Louvet but can give a couple of hints:

1. The drive rods are held on by Hex head screws not pins. Do not try pulling them out with pliers!
2. You will need to get access to the top cover of the motor block to replace the intermediate gears which are the part you list: E133761.
3. There is a good chance the entire motor block can be dropped out by removing just a few screws. Remove the bottom cover and check if there are a couple of posts that extend from the chassis through the motor block to the bottom cover. If yes, try wiggling the motor block to see if it seems to be free. It will be a good idea to replace the bottom cover without installing the screws that attach to the chassis thru-posts, if they exist, before doing this. That will keep the wheelsets in place. The wiring harness should unplug from the top of the motor block when you pull it free from the chassis.
4. The intermediate gears can be accessed by removing the motor once the motor block top cover is removed. The pull the motor straight up. Keep track of how the plastic piece with the locating pip, part No. 101, is oriented.
5. You will need to spread the motor block shell slightly to free the rods, No. 102, that the intermediate gears spin on.

If in doubt take a lot of pictures when you start disassembly to help you get it back together! The first one is always the hardest because you don't know what to expect. Maybe someone with experience working on the Corpet-Louvet will chime in on whether the side-rods and valve gear need to be removed to get at the motor block.
 

Attachments

Jon answered while I was composing my rather (overly?) lengthy response. Seriously consider his kind offer for assistance.
 
phils2um said:
Hi Martyn,

The part you have ordered, E133761, is the intermediate gear in the motor block. This is part No. 103 on the exploded diagram I'm looking at. You do not need to remove any wheels from axles to replace these. These gears spin freely on metal shafts, part No. 102, that clip into the motor block. I assume you have removed the bottom motor block cover to check the gears and that the drive gears on the wheelsets are still OK. Usually the worms on the motor shaft chew up the worm gear half of the intermediate gear and the drive gears on the wheel axles are still good. There could also be a mis-match between the spur gear half of the intermediate gear that has caused the failure. This shows where the mis-match I'm speaking of occurs: LGB 20450 and brethren drive gear issue. In this situation the axle drive gear(s) may need replacing. Hopefully not, but they may need some sideway adjustment on the wheel axle or adding some washers to the intermediate gear shaft as suggested by Dan to get a better gear mesh.

I do not have a LGB Corpet-Louvet but can give a couple of hints:

1. The drive rods are held on by Hex head screws not pins. Do not try pulling them out with pliers!
2. You will need to get access to the top cover of the motor block to replace the intermediate gears which are the part you list: E133761.
3. There is a good chance the entire motor block can be dropped out by removing just a few screws. Remove the bottom cover and check if there are a couple of posts that extend from the chassis through the motor block to the bottom cover. If yes, try wiggling the motor block to see if it seems to be free. It will be a good idea to replace the bottom cover without installing the ttttttttttttttttttttascrews that attach to the chassis thru-posts, if they exist, before doing this. That will keep the wheelsets in place. The wiring harness should unplug from the top of the motor block when you pull it free from the chassis.
4. The intermediate gears can be accessed by removing the motor once the motor block top cover is removed. The pull the motor straight up. Keep track of how the plastic piece with the locating pip, part No. 101, is oriented.
5. You will need to spread the motor block shell slightly to free the rods, No. 102, that the intermediate gears spin on.

If in doubt take a lot of pictures when you start disassembly to help you get it back together! The first one is always the hardest because you don't know what to expect. Maybe someone with experience working on the Corpet-Louvet will chime in on whether the side-rods and valve gear need to be removed to get at the motor block.
Click to expand...
That's so useful, very many thanks. Definitely a case of a picture being worth a thousand exploded diagrams. Not having yet dared open up the loco, I had clearly misunderstood the way it goes together. I suppose I also missed the clue in the wording 'intermediate gears'. I think I definitely need a grown-up to look over my shoulder, but I'm now feeling much less mystified!
 
Martyn and Jon,

Did you need to remove the drive rods/valve gear to get at the motor block? Just curious.
 
phils2um said:
Martyn and Jon,

Did you need to remove the drive rods/valve gear to get at the motor block? Just curious.
Click to expand...
The entire valve and rod assembly partly dropped away but in order to get to the top of the motor block and take off the upper plate, needed to be fully removed (two tiny screws) from the chassis. It did not need to be detached from the driving wheels, though. It was interesting to reassemble and I'm sure my extra pair of hands really did help, not just get in the way ;)
 
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