I once had trouble with a sticky rear drum on my pickup because the glue under the brake pad partially let go so the pad material would grab the inside of the drum and bunch-up all the sudden. I could see something like this causing all sorts of fun on the front end of something.

The second time I had a pulling problem was when I ended up with a weak front shock on one side which caused the truck to nosedive/lean to one side just enough that you had to steer it while applying the brakes. There was nothing wrong with the brakes, but it sure felt like it.