Angle Grinder Repair – Replacing the Pinion Gear (DeWALT Part # 623564-00)

Hi, I’m Mark from In this video, I’m going to show you how to
replace the pinion gear on a DeWalt grinder. The pinion gear mounts to the front of the
armature. Its purpose is to drive the spindle gear over
time. Over time, the pinion gear will wear and will
need to be replaced. Replacing it is easy to do, and we’re going
to show you how. Pinion gears, 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 will just make disassembly easier when
we go to separate the guard case from the housing. Next, I’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 pull the brush wires away
from the holders, pull this tension spring out of the way, and then pull 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 a reverse
thread. To remove it, I’ll need to lock the motor
from spinning. To do that, I’ll just use the spindle lock
up on the gear assembly.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’re 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 it’s secured with a
nut. It’s a 10-millimeter nut. Go ahead and remove that nut.Now the pinion
gear will slide off the shaft. Now I can install the new pinion gear. I’ll slide the pinion gear over the shaft
and secure it with the 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 to 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. 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. Again, I’ll lock the motor from spinning using
the spindle lock.Now reposition the brushes back onto the armature. Reattach the brush wire and repeat this on
the other side. Now we replace our rear housings to the motor
housing and then I’ll take a moment and make sure all the wires are tucked down to the
way so nothing gets pinched when we put the other half on. Now we’ll replace the lock button. This tab on the button needs to face towards
the armature followed by the paddle switch and then the other half of the housing. As I do this, I want to make sure the poles
on the switch and on the lock button, I’ll 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, and that looks good. Now I can re-secure the screws. Now I’ll reinstall the guard and the side-handle.That’s
how easy it is to replace the pinion gear on a DeWalt grinder. If you found this video helpful, be sure to
give us a thumbs up and leave a comment.

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