Chevrolet Repair: dull clunking sound when braking, chevy lumina, excessive corrosion

Question
i have a 2000 chevy lumina sedan! i recently replaced the shocks, brake pads, and the brake rotors! i noticed when traveling above 50 mph, when i start to brake, i hear a dull clunking sound! i don't feel anything  in the steering! and it does not do it when turning the wheel! this clunking sound only happens when braking, it sounds like it is coming from the driver's side! any clue to what is wrong?

Answer
Hey Joe,

  If this noise started right after you replaced the rotors and not before you may have a warped rotor or something even more simple yet annoying:

  When replacing front rotors on a 2000 lumina it isn't uncommon to disturb excessive corrosion on the front wheel bearing hubs.  The old rotors probably fit just fine but had left some corrosion behind that is causing excessive lateral run out of the new rotor now that it is on the old hub.  When I replace front brakes I vigorously clean the hub and rotor with pneumatic rotary tool.  The corrosion gets so bad at times it had to be chipped away with a small chisel before hand.  Pull the front rotors off and check the front hubs again.  Always apply anti seize to the hubs and check the front rotors for dark spots that may indicate a defective rotor warping when warm.


Wayne Howie