Rivets holding power window motor

Hello all. Just wondering if anyone can assist. I have finally been able to get to working on replacing the power window motor on my 96 Jimmy. I drilled off the rivet heads and got the motor off. I put the new motor in and was going to secure it with 3/16" bolts. However, I can't seem to figure out how to clear out the remaining piece of one of the rivets. It seems like it is hitting the gear that interlocks witht the motors gear to lift the window. Any ideas? Thanks for all your assistance. This is a great forum.

http://www.a1electric.com/s10motor.htm

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