The left back fender of my car got clipped on the freeway by a van a few weeks ago. Since then, it occasionally pulls to the left when I brake abruptly. I'm guessing bent rim, but otherwise the car seems fine. What do you think?

 

A bent rim would feel more like a vibration or shake while cruising. I would check for a brake problem. Depending on how hard it got hit it could also be a bent rear end housing, axle or suspension part.
Could be low tire pressure or a damaged tire also, tire damage may not be visible.

 

Switch the rear wheels ands see if
it happen or put the spare on.