Anchor
Check with a megohmmeter or a lamp powered by 220 V for a short circuit of the armature winding to ground. Voltage is supplied through the lamp to the collector plates and to the armature core. When the lamp is lit, this indicates a short circuit of the collector plates to ground. When checking, the megohmmeter should show a resistance of at least 10 kOhm. Replace the armature that has a short circuit to ground.
Using a special device, check for short circuits between the armature winding sections and the collector plates, as well as for breaks where the winding section leads are soldered to the collector plates.
Inspect the working surface of the manifold. If it is dirty or burnt, clean it with fine-grained sandpaper.
Check the runout of the core relative to the shaft journals. If it is more than 0.08 mm, replace the anchor.
Check the condition of the spline and journal surfaces of the anchor shaft. They should be free of burrs, nicks and wear. If yellow marks from the gear bushing appear on the shaft surface, remove them with fine-grained sandpaper, as they may cause the gear to jam on the shaft.
Drive
The starter drive must move freely on the armature shaft without noticeable jamming. The pinion must rotate relative to the armature shaft in the direction of armature rotation under a torque of no more than 0.27 N·m (2.8 kgf·cm). The pinion must not rotate in the opposite direction. If there are nicks on the entry part of the pinion teeth, then grind them with a fine-grained emery wheel of small diameter.
If the drive parts are damaged or significantly worn, replace the drive with a new one.
Stator
Check with a megohmmeter or a lamp powered by 220 V for a short circuit of the stator winding to ground. Voltage is supplied through the lamp to the common terminal of the winding and to the starter housing. If the lamp lights up or the megohmmeter shows a resistance of less than 10 kOhm, and also if the windings show signs of overheating (blackening of insulation), replace the housing with windings.
Lids
Check the covers for cracks. If there are any, replace the covers with new ones. Check the condition of the cover bushings. If they are worn, replace the covers as a whole or just the bushings. After pressing in, unfold the new bushings to 12.015+0,03 mm.
Check the reliability of the fastening of the brush holders on the cover from the collector side. The brush holders of the positive brushes must not have a short circuit with the "ground". The brushes must move freely in the grooves of the brush holders. Replace brushes that are worn down to 12 mm in height with new ones, having first ground them to the collector.
Check the spring force on the brushes using a dynamometer, which for new brushes should be 9.8±0.98 N (1±0.1 kgf) and, if necessary, replace the springs with new ones.
Traction relay
Check the ease of movement of the relay anchor. Check with an ohmmeter whether the relay contact bolts are closed by the contact plate. If the contact bolts do not close, disassemble the relay and clean the contact bolts and plate with fine-grained sandpaper or a flat velvet file. If the contact bolts are significantly damaged at the point of contact with the contact plate, you can turn the bolts 180°.
Information taken from the website VAZbook