How to repair flexible shaft motor grinder

Has your flexible shaft grinder ever seemed to run too hot? Or has it started making a weird grinding noise? Wait a minute, when was even the last time that you paused to do any maintenance on it? Most flex shaft motors are made to run for years and years with minimal intervention, but they do need a little TLC.


First up, Have a look at the flex shaft motor hanger housing – that’s the main, bulky part that hangs. Make a note of what model you have – this will be important for finding the right parts for your machine. On the side, probably right next to the hanger, you’ll see a black circle on both sides, most likely with a groove through the center. Found it? Great! Here’s what you do:

Tip #1 – replace the motor brushes
Using a standard flat head screwdriver, unscrew this part and just know that a part will come popping out.
This is the motor brush and it is attached to a spring.
(It’s called a brush, but it really looks like a small brick of graphite.)

Tip #2 – Lube the shaft (Seriously this is the technical term for it)
Grease it! Here’s how:

First, take off the handpiece. Most flex shafts you can simply pull it off
Look at the part just below the motor housing – where the shaft meets the motor.
Do you see a little screw on the side? Use a small screwdriver (for some models you’ll need a small Allen Wrench) and unscrew it. Be sure to set it aside in a container where you can easily find it again.