For a ?can? motor remove the worm from the connection end of the motor before any other dismantling. I?ve got a slotted piece of steel that supports the worm allowing the shaft to be driven through it. Ensure the motor body is unrestrained otherwise you might partially drive the shaft through the motor, upsetting the relative positions of shaft, armature and commutator. Once the shaft is level with the end of the worm you?ll need some form of drift. I use an old broken twist drill. The end of the worm often suffers a little damage, I?ve pondered heating the worm to ease removal but I?m concerned about heat damage to the plastic motor endplate.
Update September 2011.
Experience has shown that an intense small flame (I use a MAP Gas torch with a small nozzle) played on the worm with the motor supported as shown is effective, the motor drops under its own weight as soon as the worm is hot enough. Unlike the first method the worm suffers no damage.
Ensure both the motor body and plastic endplate are marked to ensure correct reassembly then cut both suppressor wires half way between points x and y as shown.
Prise out the three steel tabs securing the endplate in position, take care if the screwdriver slips it hurts, don?t ask! Note in this photo the locating spigot part has been loosened, unlike the earlier style of motor this type will only fit one way due to its shape.
Remove the endplate.
clean the brushgear, commutator and commutator slots as for the earlier type motor, then check the brushes and their springs. Don?t loose that small plastic washer.
Unlike for the earlier motor, these brushes need to be retracted into their holders before reassembly, this will release the small plastic washer, put it on the motor shaft and push it up against the commutator. Using a toothpick, or some other similar relatively soft tool push the brushes into their holders far enough so that the springs secure them at the side, but not so far as to protrude beyond the edge where the inner side of the motor?s body locates.
Replace the endplate assembly in approximately the same position as originally but don?t push fully home. Rotate it slightly until the top of a brush is visible in the nearest cutout to its final position.
Push the brush down with a toothpick, the spring should then locate on the brush top and press the brush against the commutator. Repeat for the other brush and then push the endplate fully home.
Bend the steel securing tabs back over, when tapping these into place ensure the motor is supported by the other endplate, and the shaft is well clear of anything underneath. If not, as with worm removal, you might partially drive the shaft through the motor, upsetting the relative positions of shaft, armature and commutator.
IMHO it?s a good idea to test the motor before these tabs are fully home.
If all is well drive the tabs home and rejoin each suppressor wire with a small blob of solder. Too much and it may foul the motor housing, but if you overdo it just file off the excess solder.
Replace the spigot then replace the worm, the hole is tapered so place it whichever way round the shaft goes in furthest.
When finally tapping into place make sure the other end of the shaft is supported with the rest of the motor free to prevent anything other than the worm moving.
Update September 2011.
Alternatively play a small intense flame on the worm until it starts to move under its own weight Use the piece of steel to finally adjust the position.
The shaft should protrude through the worm by the same distance as that on the undisturbed worm on the other end. The slotted piece of steel I use for worm removal is just the right thickness and there is a hole in the opposite end to the slot. This is placed over the shaft and tapped down until the shaft end is level with the top. File away any damage to the ends of the worm. If the damage is too great Champex Linden list spare worms so they may be available from Chalk Garden Rail.
http://www.chalkgardenrail.co.uk/acatalog/index.html < Link To http://www.chalkgardenrai...uk/acatalog/index.html
As mentioned at the end of the previous post a small amount of oil on both bearings may be good, but don't overdo it. Finally reassemble the loco and test.