35 replies to this topic

[LTD]

  I have a Dewalt 4 1/2 angle grinder. It just quit the other day for no apparent reason. Didn't burn up or anything. It is about 3-4 years old. I am goingto get a new one but I thought if I could fix this one I could have a backup. What is most likely the part that has worn out? I'm thinking brushes maybe?

[Lauber1]

9 times out of 10 in will be the brushes, but also sometimes the cord breaks right were it goes into the housing, or the switch goes bad. You will have to take and do some tests with a continueity meter to see where the trouble lies. after that you will have to disassemble and check the each part itself. Be careful and if your not up on playing with AC stuff take it to a repair shop and let them go thought it. Sometimes for no more than they cost it better to just buy a new one.

[Texas Deere and Horse]

9 times out of 10 in will be the brushes, but also sometimes the cord breaks right were it goes into the housing, or the switch goes bad. You will have to take and do some tests with a continueity meter to see where the trouble lies. after that you will have to disassemble and check the each part itself. Be careful and if your not up on playing with AC stuff take it to a repair shop and let them go thought it. Sometimes for no more than they cost it better to just buy a new one.

 I agree with Jeff on this. I repair all our angle grinders here at our shop. It is the cord 90% of the time, the switch or brushes the other 10%

[KC9KAS]

A good friend of mine once said, "An electric motor runs on smoke, and when the smoke comes out, it is shot"!

 

I agree, brushes, bad switch, or electric cord..

[glgrumpy]

They go bad alot! Even the name brands don't hold up to constant use.  I know a welding shop that has a barrel just full of broken ones. When they break, throw in barrel, get new one. They claim a fella comes around to try to make some work out of all the ones in barrel and sell back to them cheap. Most are same brand or two then.  I've had Chinese ones, lasted one session till smoke came out, had a good Bosch, acted up, think was brushes, but NOT, something in gears or bushings in front went bad. Have had Craftsman go bad and latest one is another Bosch, which seemed to last longest of ones I've had. I don't even do daily usage, just occasional as needed. Figured they would last long time, but guess not. These are NOT the cheapest ones on shelf either, about mid-range prices when I buy things.

[olcowhand]

Always been the switch or the brushes for me.  Dad uses my tools a lot & tends to put too much load on them & burns brushes out a lot.  Then the switches on variable speed drills will lose their variability & run full speed.  Very rarely a commutator will come loose, but it's only happened on our large Craftsman shop angle grinder.....twice.  The smoke left it the last time.  The great thing about name brand tools is that a decent tool supply will carry replacement parts.  Dewalt is one of the easiest for me to get parts for.

[LTD]

Thanks guys. It is not the cord. I know that for a fact. I will get some new brushes and try that. There only a couple bucks, so I can't go wrong. I haven't worked on electric motors much, but I think I can figure it out.

[olcowhand]

Thanks guys. It is not the cord. I know that for a fact. I will get some new brushes and try that. There only a couple bucks, so I can't go wrong. I haven't worked on electric motors much, but I think I can figure it out.

 

Some are very easy to replace brushes.  Does it have buttons on the outside to where you just use a slotted screwdriver to remove to replace the brushes?  Others require almost completely taking the machine apart to replace brushes.

[ol' stonebreaker]

   I'm betting it's the cord or the switch.

                                          Mike 

[philips100]

There are quite a few You Tube videos available that show how to replace the brushes on different brands of angle grinders.

[JD DANNELS]

I do not remember, does the dew alt have external broushes? I am sure my router does, there would be two caps on the side with large screwdriver slots.

[Alc]

If your going to replace the brushes take a look at the brush holders themselves , I thought my old drill was shot but there was a burr on the commutator side of one of the holders keeping the brush from making contact , someone with more exp would have picked that up right away  but I was ready to toss it lol 

i

[LTD]

It doesn't have external brushes. I took it apart tonight. It doesn't look all that complicated.There are little spring mechanisms holding the brushes in. I will see if I can get some pictures of what it looks like tomorrow.

[Texas Deere and Horse]

All My Makita's have external brushes. I have had others and they don't hold up for my at our shop. Our grinders see several hours use each day. I have 2 of these 5" grinders that are at least 8 years old, that's when I bought them when we moved our shop out here from N.C.. Those 2 were in the welding truck when we were broken into and that's the only reason I still have them.  They are also AC/DC to be used on our portable welding machines.

 

Here's a link;

http://www.northernt...CFWamPAodzjMAuA

[marlboro180]

Here is the part ya need:

 

 

 

 

Attached Thumbnails

• 

Edited by marlboro180, February 06, 2013 - 10:37 PM.