I had new brake job put on $500.00 because when you step on the brake it seems to catch. Anyway it makes the vehicle act as if you were going over bumpy road. I can't explain it. It shakes not really vibrates more like it hops or something. It also vibrates when you get up to about 80 miles an hour. I have had tires balanced and rotated, also had front end alignment. Can anyone help me find out what is wrong with my blazer. Mechanic shops don't know they tell me it is just ABS system on blazer. My friend has same blazer, and hers does not do it, so I know it is not just ABS system. They are telling me it is normal for this vehicle.