Arm 648743-00

This is a single OEM brush arm. Your tool has two of these in total, but they are sold separately. The function of this part is to hold the brush in place against the armature. It also provides a place for the brush spring to sit, which puts tension against the armature. This part can fail if the tool gets overloaded, which may cause some melting. Once your tool has been disassembled, slide the brush arm onto the post and secure it with a screw, then re-install the brush and fold the arm back against the armature. Reinstall the brush wire and make sure the spring is placed onto the brush arm, then reassemble the tool housing back together. Very simple repair that should only take a few minutes.