want to repair this tool, switch feels spongy, worked great until then

are the brushes sold together or seperate

I went and put a new battery on the grinder and pressed the trigger when it smoked out and would barely spin and now it spins little until tapped on around the switch...bad switch?

The switch on my companies' cutoff seems to have melted the plastic surrounding it. Now it won't complete the circuit most (95%) of the time. Leaving me to squeeze and squeeze the trigger to no avail. Have they updated the new switch to solve this problem? I don't want to buy a replacement just to have a failure again. I tried filing away the charred plastic covering the leads but that didn't work.

On my grinder that I took apart, the connections to the motor housing seem to be (squarish) metal pieces that slide into a slot held in by a clip. The picture above seems a bit different. ALSO, the reason it needs replaced is because, when the battery was plugged in last time it was used, the metal connectors came into contact with each other and I'm assuming kept the connection staying open, allowing machine to continue to run after trigger was released. Therefore, I'm assuming it led to shorting out the switch. (I just don't want to buy the wrong part.) Thanks :)

My Dewalt DC410 grinder was dropped and and the brush ring and the brush and lead were broken. I ordered the new parts and installed them, but I clearly did something wrong as the grinder now spins clockwise instead of counter-clockwise.

I assumed I must have installed the magnet ring upside down so I turned it around. No good. What do you think I did wrong?