Brushes & Brush Holder Test

1. Check brushes for wear by measuring amount of usable brush remaining. Replace brushes if near wear limit line. See Fig 1 . Using a digital ohmmeter, check for continuity between insulated brush holders and brush plate. See Fig 2 . Replace brush holder if there is continuity.
2. Ensure brushes slide smoothly in brush holder. Clean brush channels as necessary. Using a spring balance, measure force of brush spring. Measure force at moment brush spring separates from brush. Replace brush spring if force is less than specification. See STARTER MOTOR SPECIFICATIONS  .

Fig 1: Measuring Brush Wear

Courtesy of FORD MOTOR CO.

Fig 2: Testing Insulated Brush Holder & Plate

Courtesy of FORD MOTOR CO.