Occasionally when I push on the brake pedal it starts to go down then suddenly feels like a grind and lifts back up as if brakes aren’t engaging. Then I put more pressure and it goes down again. The first time it happened it scared the dickens out if me that the brakes had failed and I stomped on the pedal and of course jerked to a very fast stop! This is a car I bought just as a temp car and obviously has lots of issues and I don’t want to put a lot of money in but I also don’t want the brakes to fail on me. Any clues hat it might be? It’s a 2006 Buick Rendezvous.
I suspect the ABS is engaging due to a bad wheel speed sensor(s).
This will cause a sort of "grinding" noise, and will actually push the pedal back at you as the ABS pump supplies more fluid into the lines.
Does the vehicle pull to one side while braking?