Brake Electric Antilock problems of the 1996 Mercury Marquis

Mushy brake pedal when applying brakes. Dealer notified and replaced booster assembly, and condition stil occurring. Brake booster assembly failed twice. The brake pedal is still noisy and the brake booster replacing did not solve the problem.

When putting the vehicle in reverse it jerks. When putting foot on the brake pedal, it also makes a banging noise. Took the vehicle to the dealer, and was told that the problem was the rotors.