It definitely sounds like the motor to me. Your magnetic field could be cracked or you may have a short in your armature. Either way, you need to replace the whole motor before it takes out your variable speed switch. The motor comes as a sealed unit and includes a new set of brushes. Here's a link to the motor for your drill:

eReplacementparts.com : MOTOR AND PINION [396505-22] - $39.50

[quote=chrisjo;359]i have a dewalt dc988 drill that throws sparks and occasionally smoke out of the vents on the back. Good burning smell too.
Brushes looked ok, but i replaced them anyway (only $4/brush).
It still does the same thing.
Wondering whether i should try replacing the motor or what?
Motor costs about $40 on ereplacement.
Any suggestions greatly appreciated.
Cheers,
chris"
safety first, remove the power source battery or unplug the tool--- had same problem with a dewalt cordless drill-try this if you are comfortable with taking unit apart. Get to motor, remove brush box (housing)-- i'm guessing you did this to replace the brushes--with very fine sand paper clean the commutator- the part of the rotor that the brushes make contact with until you see clean copper evenly where the brush will make contact. Blow out any junk from sanding,now you will notice small grooves or lines on the commutator-using a razor blade or very small flat head screw driver(jewelers size) carefully clean out each one until you can see a separation between each, again clean out with compressed air - reassemble.tool may spark some as brushes re seat them selfs should only 5 to 10 seconds on high speed.be sure to test in safe place no flammables etc.if still a major problem go with a new motor .
Hope this helps

Tried the cleaning and no help.
Ordered a new motor and put it in today.
Works like a champ.
Thanks for the help.
As the motor came with its own set of brushes, I have a spare set of those too :)
Cheers,
Chris

[QUOTE=Mike;363]It definitely sounds like the motor to me. Your magnetic field could be cracked or you may have a short in your armature. Either way, you need to replace the whole motor before it takes out your variable speed switch. The motor comes as a sealed unit and includes a new set of brushes. Here's a link to the motor for your drill:

eReplacementparts.com : MOTOR AND PINION [396505-22] - $39.50"

I recently replaced my motor with new set of brushes included but I still have sparks after testing it. Will the sparks go away after awhile?

MIne did the same. I havea new motor on order. since that is the easy way out lol. I have no clue how to get the brushes out anyways:rolleyes:

[QUOTE=Ben;3425]I recently replaced my motor with new set of brushes included but I still have sparks after testing it. Will the sparks go away after awhile?"

Yes, there will always be some sparks, that is normal. When a new set of brushes are put in, the end of the carbon that touches the commutator on the armature is flat. That surface will quickly wear to the curvature of the commutator. The excessive sparking you initially see is from the brush wearing to that curved shape.

-UtahAV
-Mark

Great website and it is VERY easy to find parts!

I just finished replacing the brushes and have the same issue as the previous posters. So I will now buy a new motor.

Will the motor slide out once I remove the leads to the brushes?
Do I need to be concerned about anything else when I pull out the motor?

Thanks in advance for the help.