Brakes - Correcting Vibration Concerns
90toyota05 REFERENCE BRAKESNUMBER 008
DATE 09-21-90
MODEL AE92-
TITLE COROLLA BRAKE VIBRATION
One of the major causes of brake vibration is rotor thickness variation. The term "Thickness Variation" is not to be confused with rotor runout. Thickness variation is the difference in rotor thickness as seen in figure "A". Rotor runout is the deflection of the rotor as it is spinning; as seen in figure "B".
Driving several thousand miles in a vehicle with excessive rotor runout could cause an uneven wear on the rotors resulting in thickness variation. This is caused by the pads constantly making slight contact with the rotor; even if the brakes aren't frequently applied. Also, rust, high humidity, road salt, and sea breeze accelerates rotor wear resulting in increased thickness variation.
When correcting brake vibration, follow the procedures outlined following page.
(FIG. 1):
REPAIR (INSTALLATION) PROCEDURE:
1. After removing the rotors, clean the contact surface between the axle hub and the rotor with a wire brush to remove any rust that may have built up.
2. Temporarily install the new rotor onto the axle hub and tighten all four lug nuts evenly to (76 ft.lb. or 103 N-m) with a torque wrench .
3. Mount a magnetic base dail gauge as shown in FIG. 1, and measure the runout at a point of 10 mm (0.39 in.) from the outer edge of the rotor.
(FIG. 2):
4. If the rotor runout exceeds 0.0020 in. or 0.05 mm, reposition the rotor clockwise to the next hub bolt for phase matching. Retorque the lug nuts and recheck the runout again.
5. If the rotor runout is still out of the specified limit (0.0020 in. or 0.05 m), replace the axle hub with the new (Part No. 43502-12080).
6. After reconfirming that the runout is within spec's (0.0020 in.), install the caliper, pad kit (04491-12431) and wheels. Torque the lug nuts using a cross pattern as shown in in FIG. 2 to 35 ft.lb. (47 N-m). Then retorque to 1050 kg-cm (76 ft.lb. or 103 N-m).
Caution: DO NOT use an air impact wrench to tighten wheel lug nuts.
PART NUMBER INFORMATION:
New P/N Previous P/N Part Discrintion
# 04491-12431 - - - New Pad
Kit, Front Brakes
43512-12320 43512-12250 Disc, Front
* 43502-12080 43502-20080 Hub Sub-Assy, Front Axle
# This pad kit should only be used on vehicles with the complaint of brake vibration. on all other brake repairs, use the previous part number 04491-12401.
* Replace only if the rotor runout exceeds (0.0020 in.) after installing the new rotor onto the original hub.
INTERCHANGEABILITY:
All parts are interchangeable with previous parts.
MODEL APPLICATION:
AE92- From 1988 to 1990.