Steering - Vibration/Brake Pedal Pulsation: Overview

Classification:
BR00-001

Reference:
NTB00-013

Date:
February 10, 2000

AMMCO ON-CAR BRAKE LATHE OPERATING PROCEDURE

APPLIED VEHICLES:
All Nissan vehicles with disc brakes

SERVICE INFORMATION

If a Nissan vehicle exhibits steering wheel vibration or brake pedal pulsation when braking, it may be brake judder. Brake judder is created by excessive thickness variation of the brake rotors. In most cases the thickness variation is a result of excessive brake rotor run-out. While brake judder is usually associated with the front brake rotors, the rear brake rotors may cause it too.

The most effective way to eliminate brake judder and excessive rotor run-out is to turn the brake rotors using the Ammco on-car brake lathe. This required special tool will minimize the assembled brake rotor run-out more than conventional off-car turning/installing on hub process. Please note the following points when using the on-car brake lathe:

^ Prevent metal shavings from contacting or collecting on the ABS speed sensors. Remove any shavings that stick to the ABS speed sensor's magnet. It is best to clean the ABS sensor with the rotor removed.

^ Mark the exact location of the rotor (on the axle hub) before removing the rotor (see Figure 2).

^ Do not tighten the wheel lug nuts with an air impact driver. Uneven or high torque applied to the lugs may distort the brake rotor and hub, resulting in increased rotor run-out and excessive rotor thickness variation as the rotor wears.

^ If new rotors are required, install them on the hub in different positions (index) to achieve the lowest run-out reading (equal to or less than 0.0012", 0.03 mm), using a dial indicator. See Figure 11.