GENERAL AR 4649656 - Caterpillar

Table 1
Tools Needed
6V-7070 Digital Multimeter Brush Holder - Test
Illustration 1 g00716313
Brush holder test
(6) Brush spring
(7) Brush holder
(8) Brush holder plate
Check the brush springs (6) for damage or rust. If necessary, replace the brush springs.
Place the multimeter in the "20M Ω" range. Touch one meter lead to each positive brush holder (7) and the other lead to brush holder plate (8). Check the three positive brush holders (7).
Each multimeter reading should be greater than 100,000 Ohms. A meter reading of "0.10" or a value that is greater is acceptable.
If the meter reading is less than 100,000 Ohms, the brush holder is grounded. The brush holder must be replaced. Brush Length - Check
Illustration 2 g00716319
Brush length measurement
(X) Brush length
Measure brush length (X) for wear. The new brush lengths are 19.1 mm (0.7520 inch) to 19.8 mm (0.7795 inch). The minimum brush lengths are 10.0 mm (0.40 inch).
If the brushes are worn below the minimum length, replace the brush holder.