Tip of the Week 5/30/10- Preventing Brake Rotor Chatter

Brake disk chatter can be very annoying. It is the vibration or shake you will feel when you press on the brake pedal, particularly when braking from high speed. At low speed you will feel a pulsing in the brake pedal as you come to a stop - almost like a tire is out of round. This is usually cause by a brake disk that is out-of-round ( or like a potato chip). If it has been occurring for a while and has progressively gotten worse rotor replacement is the only cure ( resurfacing Mercedes brake rotors is not recommended and most likely will not be a permanent cure). If it happens right after installing new rotors then you should act immediately to fix the problem BEFORE the new rotor is permanently damaged. Here are the actions you should take:

• 1. Loosen all lug bolts, then retighten progressively and evening until you reach the maximum torque of 85 ft pounds (always use a torque wrench) on each bolt.
• 2. If that does not improve the "chatter" then there is a possibility the rotors did not get mounted flush to the hubs. This is usually caused by rust buildup on the face of the hub.

Remove the rotors and thoroughly clean the hub with scotch bright pad. These are available to be mounted on air sanders and die grinders as shown. If this is not available you can use 100 to 220 grit sandpaper. Use the finest grade available to do the job. NOTE: When installing new rotors ALWAYS clean the flat surface of the hubs thoroughly!