First off I'm not a master mechanic but I chase fine good bit of shade tree mechanic work. I changed the brake pads on my wife's 2012 traverse yesterday. I pumped the brake to attain pressure again and drove back and forth in driveway to test. Today she went for a drive and said it was bouncing. I got in sure enough as soon as I exited the driveway I could feel it was very different. It felt stiffer but bouncing almost at same time. What did I screw up? I even tried swapping back to old pads and same thing. Help please.!!