Question about Dewalt Small Angle Grinder 4 1/2"

1 Answer

Dead DW400 angle grinder

My dewalt dw400 angle grinder is dead. It worked just fine last fall, then the first attempt this spring - nothing. Can the brushes be worn after two seasons of mower-sharpening duty?

Posted by on

  • David Ford
    David Ford May 11, 2010

    I would have to think not. What could be the case depending on where it was stored is dirt or oxidation in the area of the brushes. What I would try first is unplugging and look at the cord for breaks and then turn the wheel by hand forward and backwards a couple times and then plug back in the try it. Let me know if this helps and if not we will dig into it deeper



1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that gotĀ 5 achievements.


    An expert whose answer gotĀ voted for 20 times.


    An expert who has written 20 answers of more than 400 characters.

  • Expert
  • 42 Answers

Some of those double insulated power tools have a remote switch. By remote I mean that the piece you push, or pull does not actually have a switch on it, but has an arm or rod that could be several inches long, and that arm or rod actuates the switch.

If that 'arm' which is usually plastic breaks, the unit won't turn on (or in some cases off)

I have had a Dremel tool and a haircutting clippers that did exactly what you describel

Make sure it is not plugged in, then remove the phillips screws holding it together. Many times there is one hidden and you have to look for it.

Gently -- Gently separate the two pieces of the body. I like to do this over a white beach towel so that any pieces that might jump out at me won't go far and be easy to spot on a white background.

Look for an arm that reaches towards a switch --if it is broken it will be obvious.

I repair that kind of break with JB Weld. Don't get the quick dry JB, but the 'normal' product. Quick dry gives you almost no 'open' time.

Just mix a tiny dab of material from each tube together on something non-porous e.g. a piece of scrap ceramic tile, broken dish, glass, mirror and put a little of the mixture on each part of the broken area.

Put the two pieces together and let dry -- for 24 hours.

Re-assemble and you are home free!

I always have a plan for clamping or propping the repaired part so that it won't move BEFORE I mix the epoxy. That way I am not scampering around trying to find what I need whilst trying to hold it together.

Many times I use a tiny screwdriver and dip it into the mixture and apply it with the screwdriver. As long as you wipe the screwdriver clean with a paper towel it will be fine.

good luck.

Posted on May 18, 2009


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya Repairman can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US.
click here to Talk to a Repairman (only for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Fixing bad motors in dewalt angle grinders power tools

it would be much better if you bought a new one because it would be cheaper

Jul 04, 2014 | Dewalt DW824 5" Electric Angle Grinder

1 Answer

Grinder will not turn on

Maybe carbon brushes or motor.
Unscrew and pull back cover nearest cord.
Brushes should be touching rotor, the copper segments, and not too short. Smell for burnt offerings from the motor.
Some tools have thermal protection too.
See if there's a thermal fuse, which looks like a small shiny rod with a wire each end.
It could be inside sleeving.
On an electric motor, this is usually embedded in the stator, or field windings.**
This may have blown if grinder got too hot..
**Would need complete strip-down to inspect.
If motor is cooked, get wallet out.
Motor-parts/repair labor may cost more more than a new grinder.
Carbon brushes:
Take sample to store, with make/model of grinder.
Brushes fairly cheap.
Hope this helps,

Oct 19, 2017 | Dewalt Small Angle Grinder 4 1/2"

1 Answer

Dewalt dw 400 grinder is locked up

Two things come to mind. One the drive head (gear box) has failed. Remove the cover from the gear box and see what is going on in there. Second, do you know the button you push to lock the drive so can remove or install (tighten) a new wheel? Make sure it is releasing. Most of these are spring loaded and if that spring fails the lock mechanism can stay engaged. Hope this helps.

Jun 14, 2010 | Dewalt Small Angle Grinder 4 1/2"

1 Answer

Fault on a Kinzo 115mm Angle Grinder

Hi J,

Hopefully you just wore out the brushes. Replacement kits are available for a few bucks and the fix is pretty easy.

On the darker side, If it overheated enough that it burned the windings (insulation melts, shorts, badness), there isn't much you can do unless it's still under warranty.

You won't know until you get it apart. You'll know which it is at a glance.

Unplug it and dismantle the base of the grip where the cord is attached.

The brushes are small spring loaded graphite blocks that transfer electricity to what looks like a cylinder around the central drive shaft that has a lot of vertical copper strips on it. They are normally housed inside small copper tubes opposite each other.

If those tubes are empty but for the spring, it's brushes.

If the insides are full of ashy residue, it's not the brushes

Best regards and I hope it it's the brushes


May 27, 2010 | Dewalt DEWD28110 Heavy Duty 4 12"...

1 Answer

DeWalt DW400 4 1/2'' angle grinder stopped working -suspect a bad switch? Any other causes? How do I troubleshoot? Thanks, Steve

have a look at the drushes first they do wear out fast
then give the switch a splash of WD40 if that dont sort it give up? its a good make but it wont live forever

Oct 23, 2009 | Saws

1 Answer

My dewalt dw 402 grinder, starts fine, runs for a few minutes and then shuts down. Brushes appear to be fine.

Pull it apart and clean the armature, you will find something between the brush contacts getting larger and making contact thus shorting it out, so clean the armature with fine point object do not gouge the material out of the area between the copper plates. Also blow out any metal dust you may see.

Jul 31, 2009 | Dewalt Small Angle Grinder 4 1/2"

1 Answer

Dewalt dw474 grinder quit

you need new brushes. carbon is meant to be touching the armature not the contact from the spring. Its worn down

May 10, 2009 | Dewalt DW824 5" Electric Angle Grinder

Not finding what you are looking for?
Dewalt Small Angle Grinder 4 1/2" Logo

374 people viewed this question

Ask a Question

Usually answered in minutes!

Top Dewalt Saws Experts

Doctor PC
Doctor PC

Level 3 Expert

7733 Answers

Parson's Repair...
Parson's Repair...

Level 2 Expert

206 Answers


Level 3 Expert

2453 Answers

Are you a Dewalt Saw Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides