Starter faults in the electric motor, drive and solenoid: worn bearings and brushes, winding shorts and a sticking drive.
The starter is a reliable, short-duty component, and the life of many of its parts depends more on the number of starts than on mileage. Faults usually originate in the electric motor, the drive or the solenoid.
- Worn armature bearings cause imbalance and knock-on failures.
- Fluid leaks contaminate brushes and commutator, raising resistance and reducing power.
- Worn brushes increase sparking, and their dust can short to the housing.
- Prolonged cranking weakens brush springs and damages winding insulation.
- Dirty splines make the drive stick, while poor installation damages the pinion teeth.
During repair, the bearings should always be checked in addition to fixing the primary fault.