Angle Grinder Repair – Replacing the Front Armature Bearing (DeWALT Part # 330003-60)
Angle Grinder Repair – Replacing the Front Armature Bearing (DeWALT Part # 330003-60)

Hi, I’m Mark from In this video, I’m going to show you how to
replace the armature bearing on the DeWalt grinder. The armature in your grinder spins at very
high RPMs and after years of use, the armature bearings are going to wear out. Replacing them is easy to do and we’re going
to show you how. Armature bearings, as well as many other parts,
can be found on our website. Let’s get started.We’ll begin by removing
the side handle and the guard. This would just make disassembly easier when
we go to separate the gear case from the housing. Next we’ll separate the two halves of the
rear housing. Next, I need to pull the brushes away from
the armature. To do that, I’ll put the brush wires away
from the holders, pull this tension spring out of the way and then put the brush arm
back. I’ll repeat this on the other side. Now I need to remove the separator fan from
the rear of the armature. It just simply screws on, but it is reverse
thread, and to remove it I’ll need to lock the motor from spinning. To do that, I’ll just use the spindle lock
upon the gear assembly, and now I can remove the fan.Next, I’ll separate the gear case
assembly from the motor housing. It’s secured with four screws. Now I want to separate the armature from the
gear case assembly. At this point they are just connected by a
bearing that’s pressed into the gear case, so I’ll just pull the two apart. With the armature separated from the gear
case, now I can go ahead and remove the pinion gear. First I’ll wipe the grease off of it. Now you can see that its secured with a nut. It’s a 10-milimeter nut. Go ahead and remove that nut, and now the
pinion gear will slide off the shaft.Now I’ll remove the front armature bearing. This bearing can be challenging to remove
because you have zero clearance at the rear of the bearing for a bearing puller. I’ve had pretty good success using a couple
of screw drivers behind the bearing and I’ll just pry the bearing off. However, if the bearing is seized onto the
armature shaft, removing it with the screw drivers won’t work. Your best bet at that point is to use a press
and press against this bearing-retainer plate. However, you will likely damage the retainer
plate removing the bearing this way, and you’ll need to replace the plate as well.We’ll give
the screwdrivers a try and see if we can get it off that way. It looks like its going to come out fine. Now we can install our new front armature
bearing. I’ll slide it over the shaft and using a socket,
I’ll place the socket onto the bearing and then use a mallet to tap the bearing in place. Now I can install the pinion gear. I’ll slide the pinion gear over the shaft
and secure it with a nut. Now we can reassemble. I’ll start by inserting the front end of the
armature into the gear case assembly.I need to make sure I line up these tabs on the bearing
plate with the slots in the gear case. Now I’ll just slide the armature and gear
case assembly back into the motor housing and I’ll secure the gear case housing to the
motor housing with the screws. Now I can reinstall the separator fan. Remember it’s a reverse thread, and again
I’ll lock the motor from spinning using the spindle lock. Now I’ll reposition the brushes back onto
the armature, reattach the brush wire and repeat this on the other side.Now we’ll replace
our rear housings to the motor housing and then I’ll take a moment and make sure the
wires are tucked out of the way so nothing gets pinched when we put the other half on. Now replace the lock button. This tab on the button needs to face towards
the armature, followed by the pedal switch, and then the other half of the housing. As I do this, I want to make sure the posts
on the switch and on the lock button all line up properly with the housing. Once I get it in place, I’ll just test everything
real quick to make sure it’s right. That looks good, so now I can resecure the
screws. I’ll reinstall the guard and the side handle.That’s
all it takes to replace the armature bearing on a DeWalt grinder. If you found this video helpful, be sure to
give us a thumbs up and leave a comment.

3 thoughts on “Angle Grinder Repair – Replacing the Front Armature Bearing (DeWALT Part # 330003-60)”

  1. Oddmund Bjornaali says:

    Check the gearbox and renew the grease!

  2. Pro1er says:

    One of your better videos.

  3. Ba. Moayyd says:

    ist sehr gut .

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