Lucas Headlamp Pod Motor Stripdown sequence and Maintenance Guide
A pod motor. Some of them (notably earlier variants) were painted with a rubbery coating that helps to repel water. Quite often, under this coating the motor will be in mint condition. Later units had a basic black paint coating that doesn’t survive as well. This unit has had the switch box cover screws removed: the remaining screw serves to retain the switch box to the gear housing. The knob at the bottom of the motor allows the armature to be turned manually to raise the pods in the event of a power or component fault.
Contact Diode Motor Terminals Common Contact Diode With the switch box cover removed, the switch assembly, diodes and motor connectors are accessible. Removal of the remaining screw….
Plunger Plunger Rivetted contact … allows the switch box to be removed. This is the view of the other side, showing the rivetted contacts and the nylon plungers that lift the terminal strip.
Main Gear Motor Worm Ramp With the switch box removed, the gear assembly is revealed. The motor worm is steel, driving the nylon pinion of the main gear. The ramp on the main gear lifts the plungers of the switch box to stop the gear in either of two positions.
The main gear should slide out of the housing; one of the shaft bearings can be made out in the photo above. The nylon gear lasts quite well despite being turned by a steel worm; chewed or broken teeth indicate damage caused by, e.g. siezed linkages or pivots, or impact. Note the dished washer on the shaft (right).
Removal of the two through-bolts allows the motor casing to be separated from the gear housing. Note the nylon thrust bearing on the end of the worm.
< Remove the three screws that secure the motor brush assembly... … and lift away the brush assembly. In this photo, the top armature bearing can be seen, with its retaining spring. The brushes are in good condition and fit for re-use.
Pull the manual control knob off the end of the armature and carefully remove the armature from the motor casing. You have to fight the stator magnets, of course…!
Laminated Core Bottom Bearing Commutator Top Bearing Washer stack Windings This armature is in pretty good shape. The brushes tend to wear the area of the commutator that is ‘swept’ by them. Retrieve any washer stack that may be present: washers may stay on the armature or get stuck to the motor casing lower bearing.
The commutator should be polished with a fine abrasive (I’m using 1200 grit Wet’n’Dry here) and the gaps between the segments cleaned out with a suitable implement (craft knife blade etc.).
The armature endfloat should be set using this screw (later versions have a screw and locknut arrangement). On reassembly, line up the engraved line on the motor casing with the arrowhead on the gear housing.
Don’t forget to replace the manual control knob! On later variants the knob design was changed to incorporate a one-way clutch, so that only anti-clockwise movement of the armature is possible.