Grinder Repair – Replacing the Front Bearing (Makita Part # 210042-8)
Grinder Repair – Replacing the Front Bearing (Makita Part # 210042-8)


Hi, I’m Mark from eReplacementParts.com.
In this video I’m going to show you how to replace the front armature bearing on a
Makita grinder. There are two bearings on the armature inside your grinder; one on the
rear and one on the front. Like any bearing, eventually the armature bearings will wear
out and need to be replaced. Common signs of a bad bearing will be a squeaking or squealing
sound coming from the grinder. Replacing the front armature bearing is easy
to do and I’m going to show you how. Front armature bearings, as well as many other parts,
can be found on our website. Let’s get started. I’ll begin by removing the side-handle and
the guard. The gearbox housing is held in place with four screws. I’ll go ahead and
remove those. Now I can remove the rear housing. It’s held in place with a single screw.
Now I’ll move the brush springs to the side of the brush holder. This will remove the
tension from the brushes so they’re not pressing against the armature. I’ll do this
on both sides. With the tension removed from the brushes, now I can go ahead and remove
the armature assembly. Now I’ll remove the drive gear. It’s secured
with a nut. Now I’ll remove the front armature bearing and the gear housing cover from the
armature. To do that, I’ll place the cover in the open jaws on my vise. Then using a
rubber mallet, I’ll tap the armature shaft away from the bearing. With the armature removed,
now I can remove the bearing from the gear housing cover. To do that, I’ll again place
the cover on the vise jaws and I’ll use a socket that has a diameter that’s the
same as the inner race diameter on the bearing. I’ll go ahead and tap the bearing away from
the cover. Now I’ll install our new front armature bearing. I’ll place it in the gear
housing cover and this time use a socket that has a diameter the same as the outer race
on the bearing to tap it into place. Now I can install the gear housing cover assembly
back on to the armature. I’ll seat the bearing back on the armature shaft using a socket
that has a diameter the same as the diameter on the inner bearing race. Now I can reinstall the drive gear and secure
it with a nut. Now I can install the armature assembly back into the grinder. I’ll reinstall
the gear housing assembly to the motor assembly and secure it with the four screws. Now I’ll
reposition the brush spring back over the brush. Now I’ll slide the rear cover back
over the motor housing and secure it with a screw. I’ll finish up by installing the
guard and the side-handle. And that’s all it takes to replace the front
armature bearing on a Makita grinder. If you found this video helpful, be sure to give
us a thumbs-up and leave a comment.

4 thoughts on “Grinder Repair – Replacing the Front Bearing (Makita Part # 210042-8)”

  1. Phil falzone sr says:

    thanks for the video

  2. Esekiel Bascos says:

    thanks for the nice video.

  3. Paul Day says:

    Thanks for the video. Do you have to regrease the gear housing before sealing it up?

  4. svtrader says:

    Complete BS he used the old bearing!

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