Question about Milwaukee 5321-21 Rotary Hammer

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Wont run continuously

When i press trigger it runs for about ten seconds and then stops. you repress the trigger again and it runs for ten seconds again. it just will not stay on until i say when. whats up with this thing

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  • cynjun Sep 26, 2008

    no this is not the fix. it did not work.

  • David Ford
    David Ford May 11, 2010

    I would look at the brushes and clean area with compressed air. Sometimes the brushes get hung up in the holder and make intermittent contact. Second if this tool is not that old it might still be covered under warranty. Good luck


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Hold the button in all the way

Posted on Sep 26, 2008

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you should only get voltage at the brushes when the trigger is pressed... is the tool constantly running or is it doing nothing?
If your getting voltage to the brushes and its doing nothing... check the brushes to see if they are worn out and not touching the armatures commutator. Replace them and the switch

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I got a bosch 11236vs

Don't rule out nothing. All it takes is it to run on a too small and/or too long extension cord. Also if you ran it on a generator that not keeping up the voltage. The good news is takes no time to check. First remove the bottom cover by removing the center plug with a allen wrench. Then the 4 screws on the outside of the plastic. Gently pry the cover off, it's tuff and you may need a screw driver. Now you have access to the brushes, remove them and check the wire connecting them, if it's discolor (should be bright silver) then you had a low power problem and they need replacement. While in here chech the end of the armature. Too get it out you must remove the brush holders. Just disconnect the wires and pull them out with needle nose plyers. The armature should be bright and without any cracks in the segments. You can clean it up a bit with sandpaper 180 grit or finer. When reassembling ensure you notice that the end piece off the casing has a v-notch in it that lines up with a notch in the bearing end plate. Next check the cord. Remove the on/off switch by gently poping it off with a screwdriver. Remove the screws under the switch. Then remove the the handle bolt that go side to side. Now you should be able to split the handle. With a meter do a continuity test form each pin of the plug with the wires at the connection point in the unit while moving the cord around. A short in the cord may only show when the cord is in a specific position. If this does not find the problem then you need to check accross the switch. Check continuity of the white wire in to the white wire out with a meter while the trigger is engaged and repeat with the black. Also check with the same meter white to black on both sides of the switch, you should have no continuity. This also goes for the cord. This should do it. If not let me know.

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