Carbon Brush
16
The BBM307/YBM307 Block Buster Mini Masonry Saw uses a high horsepower low amperage air over
brush motor.
Replace the brushes when the motor begins to lose power. Brushes typically need to be replaced
During the life of the saw.
Replace the brushes when over 2/3 of their original length is used (when the over all length of the brush
is less than 7/16” (11.1mm). It is normal for the brushes to wear down.
Brush Replacement:
1. Disconnect the electrical supply
2. Remove the Air Filter.
3. Remove the four (4) Motor Air In-Take Cover mounting screws (see Figure 4-1: Motor Air In-Take
Cover Removal).
4. Remove the Motor Air In-Take from the motor.
5. Use a coin or wide blade screw driver to remove the Carbon Brush Cap. Use care not to damage the
Carbon Brush Cap. Inspect the Cap for damage. If the Cap has any signs of damage replace (see
Figure 4-2 Carbon Brush Removal)
6. Remove the Carbon Brush.
7. Use compressed air to blow any access carbon build up out of the motor.
8. Inspect the inside of the motor by looking into the brush holder for any excessive wear or carbon
Build up.
9. Place the new Carbon Brush into the Carbon Brush Holder.
10. Replace the Carbon Brush Cap and tighten the Cap with a coin or wide blade screw driver. Only
snug the Cap down. Over tightening the Cap can cause damage to the Cap.
11. Reinstall the Motor Air In-Take Cover and re-attach the four mounting screws. Do not over tighten.
12. Clean the Air Filter.
13. Reinstall the Air Filter.
Figure 4-1: Motor Air In-Take Removal
Figure 4-2: Carbon Brush Removal
Cutting Head
Brush Cap
Carbon Brush
Motor Air In-Take Cover
Brush Cap
Carbon Brush
