Brake Disc Rotor problems of the 2000 Volkswagen Jetta

I am the primary repair person for this vehicle. Over its history, there have been numerous component failures that in my opinion are unacceptable for a vehicle with this mileage and age. I personally know the owner, and know that it is not operated under unusually harsh conditions. The vehicle was involved in a minor cosmetic crash early on, otherwise, there have been no unusual outside factors. At this point, the car has only 37,000 miles on the odometer. Primary use is on long trips. The vehicle is parked and stored for about 3-6 months each year. First problem: air conditioning system leak: the expansion valve failed, requiring replacement. Check engine/ malfunction indicator light: has come on several times, each time with the same dtc, a manufacturer specific code related to the mass air flow sensor. The power windows have failed, ultimately resulting in free repair of the windows with a revised retaining clip, as this problem occurs far too often, and finally, the rear brake pads have worn completely with the front pads in virtually new condition. This is accompanied by all four rotors being excessively pitted, with large areas of the rotor face actually flaking off. My research shows that I may end up needing to replace the rear calipers, as well, due to poor design.

Rear brakes on vw Jetta -- calipers seized, rotors ruined, pads metal-to-metal. Front brakes virtually in factory condition.

Rear brakes/rotors worn out at 23,000 miles (no explanation given).

Consumer called complaining about gas recirculation valve ( egr valve). Vehicle won't accelerate even though she wa s stepping all the way on the gas pedal. Dealer was contacted, and stated that the vehicle was out of warranty. Had to replace brakes and rotors at 35000 miles, which she thought that it was not usually normal on any vehicle.