Dremel 4000 Shaft Lock Pin Replacement

Written By: John Cobb

Comments: 10

Difficulty

Very easy

Steps

Time Required

6 minutes

Introduction

This is likely the simplest repair possible for this device. Simply access the shaft lock pin after opening the case.

Tools

Parts

Shaft Lock Pin

Step 1

Start by removing the housing cap by unscrewing it.
Next, unscrew the now exposed collet nut while holding down the shaft lock button.
To remove the collet nut, you may need to use the small open-end wrench provided with the Dremel.

Is this a joke??? Wanna maybe possibly tell US WHAT A COLLET NUT LOOKS LIKE?? I mean it's obviously very exposed (not exposed one bit. My Dremel 4000 looks exactly like it did before. No Collet nut suddenly stood out) and not all of us have advanced degrees in Dremel parts

Jeff Wagner -

Dam Jeff. I am not sure if you are being sarcastic or not, but maybe you should go lie down for while.

itguyfla -

Step 2

Using your hands, carefully remove hanger from casing.

Mine seems to have solid caps without the slot. How are this type removed?

claire roche - 19/10/20

This is getting worse. Maybe skipping the Collet Nut part threw me off - as there is no hanger. This description is PATHETIC!!!

Jeff Wagner -

I love how these pictures show you NOTHING related to what this guy is talking about

Jeff Wagner -

Wow, you guys are really amazing. Are you actually working on a Dremel 4000? Mine looks exactly like the pics. It has a hangar on it, as well as a collet nut.

itguyfla -

Step 3

Remove the brush caps (one on each side) by using a flathead screwdriver bit.
The brush caps are spring loaded.

I have found that the brushes are the most likely failure point on the Dremel tool. I haven’t purchased a new one in many years but they used to come with a spare set.

In general commutator brushes are made of a soft high carbon compound, usually found with new springs attached. The brushes can be carefully reshaped using files, sandpaper and a razor knife to fit the recesses of the tool.

Use the original to get necessary dimensions, a dial caliper is very helpful here to duplicate channels and recesses as well as determining how long the brushes should be. Should you need to shorten the brush a new concave can be established using a pencil or dowel wrapped in sandpaper being sure to match the concave to the channels so it matches the armature. It is preferable the curve be wider than the armature so edges don’t catch, it will naturally wear into a perfect curve. Blow off before installing.

Once the tool is reassembled turn on and off several times then run for a while varying the speed.

George McNew - 27/07/22

Step 4

Using the Torx 15 screwdriver tip, remove the 5 screws (12.5 mm) that hold the casing together.

Step 5

Use a plastic opening tool to gently wedge apart the hard plastic threads.

Step 6

Use your hands to carefully remove the back casing so that none of the components fall out.

Step 7

If the shaft lock pin is not engaging the rotary gear, or if the spring is missing or damaged, it will need to be replaced.
Remove the damaged shaft lock pin and spring by hand.
Place new shaft lock pin so that the spring functions and the lock engages the rotary gear.

Conclusion

To reassemble your device, follow these instructions in reverse order.

Author

John Cobb

Member since: 20/01/16

1740 Reputation

3 comments

These instructions are idiotic! I want to replace the shaft lock pin because it is not WORKING. Step 1 instructs me to use the shaft lock pin to remove the exposed collet nut. The reason I am changing the shaft lock pin is because it won’t hold the shaft for loosening the collet nut. DUH!

mitchthane - 27/10/17

three years later and I came to the same conclusion: DUH

Randy Martin - 16/11/20

Four years later and I came to the same conclusion: DUH

Ben simon -