The cause of shuddering brakes is commonly misdiagnosed as warped disc rotors, which is rare in modern cars under normal operating conditions. It is more likely that friction material from the brake pads has been unevenly deposited onto the disc. However, in this case we would suggest getting a second opinion from another workshop. All RAC members are entitled to one free fault diagnosis per membership year. To utilise this benefit, call 13 17 03.