RobinofLoxley Posted June 19, 2020 Share Posted June 19, 2020 Hello folks. I have a number of locos with the above tender drive and as I am operating the locos more and more, having been in 'cold storage' they are failing with the same trouble, namely this pinion gear working loose so that the motor simply spins. Sometimes a rest, i.e cooling down, results in traction again but often not. I have replaced a few but eventually the problem reappears. Is it better to take the locos to a specialist for repair rather than diy? Is it an option to 'weld' them in place with superglue for example? (One motor on a King Class looks as though that has been done but not superglued). Thanks. Link to post Share on other sites More sharing options...
bigherb Posted June 19, 2020 Share Posted June 19, 2020 I usually just replace them with the brass ones available from Peters Spares ect. The silver cast ones regularly slip on the shaft. Link to post Share on other sites More sharing options...
Amand Posted June 20, 2020 Share Posted June 20, 2020 It's a fairly easy fix, to avoid damage remove the gear retainer and the 4 plastic gears. I take the front plate off (where the carbon brushes are held). To do this you may also need to remove the drive wheels, they will come off the axle at the geared side. If there are screws holding the carbon brush holder arms then remove them - in some generations of ringfield the screw will extend into the metal block. The face plate has four clips, take care as the plastic can become brittle. Placing the armature spindle facing down on a solid metal surface, put the replacement cog on the shaft. There's a collar inside the cog, this deforms and grips it in place. Using a nut spinner that has a hole larger than the axle diameteror tap the cog into place. It needs to be a hairs width above the metal bearing. Apply oil sparingly between the cog and bearing. Before assembling the motor, check the condition of the armature. Using IPA and a cotton bud give it a clean including the gap between the segments. If the ends of the carbon brushes aren't level then other use a file to flatten them off, or replace them. It's usually a sign of a loco that been run in one director more than the other. Using electrical cleaning fluid clean the bearing insides and wheel axles. Apply was tiny drop of Peco Power Lube to the axles then re-assemble in reverse order. The part from Peter's Spares is PS94. Same price on eBay as the web site, but postage is only £2 on eBay but £4 in the web site. Link to post Share on other sites More sharing options...
RobinofLoxley Posted June 20, 2020 Author Share Posted June 20, 2020 Thanks Amand. When I have done this (possibly not with the brass gear mentioned above, which I assume is a requirement) I have done part of the strip down then used a G clamp with a nut as you describe glued to one end, I have screwed the new cog into place using the clamp. Cleaned and lubricated as required (though not with IPA I thought that was what my local sold pre lockdown) and reassembled. Loco has alwas run well after until the cog gets loose again. The first time this happened I could see a hairline crack in the cog, but not on subsequent failures. Maybe they are just not visible on each one. I wasn't aware of the collar, is it a feature of all replacement cogs?? Link to post Share on other sites More sharing options...
Amand Posted June 21, 2020 Share Posted June 21, 2020 The brand new ones have the collar is 1/3 of the way in the cog, so insert it so that the 2/3rds covers the ale, makes it much easier to fit . Guessing that the collar deforms slightly and that grips the axle. I've had a few silver coloured ones (Aluminium?) fail, but the brass ones seem to last, whether the original ones from the 1970s or the new replacements from Peters Spares. With practice its 1/2 hour job. Link to post Share on other sites More sharing options...
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