Brakes - Pedal Pulsation/Vibration

9211porsche01

March 10, 1992


Model
All

Part Identifier
4064/68
4650/53


Group
4

Number
9203


Subject: Brake Disc and Wheel Hub Run-Out


ATTENTION: Service Manager/Service Technician

Models Affected: All


Concern: Brake pedal pulsation/vibration. Checking brake disc and wheel hub run-out


Repair Information: When repairing brake pedal pulsation or vibration, the brake disc and wheel hub lateral run-out must be measured.

Work Procedure: 1. Check, and if necessary, adjust wheel bearing play.

2. Remove wheel and install adaptor plate tool number 9510 or steel spacers. Torque wheel lug nuts to 130 N-m (96 ft.lbs.).

3. Install dial gauge with suitable gauge holder. Use a dial gauge pin with a large base. Place gauge pin on largest diameter of brake surface. Set gauge with approximately 2 mm pre-load, rotate disc and record run-out Maximum assembled permissible run-out: 0.10 mm.

If disc run-out is more than 0.10 mm, remove disc and measure runout on inside and outside brake disc surface, on a brake lathe. Maximum permissible run-out with disc removed: 0.05 mm.

Measure also wheel hub lateral run-out. Install dial gauge with suitable gauge holder. Place gauge pin on largest diameter of wheel hub. Set gauge with approximately 2 mm pre-load. Rotate wheel hub and record run-out. Maximum permissible run-out: 0.05 mm.

4. If necessary, machine brake disc and/or replace wheel hub. Refer to specifications and wear limits published in the Workshop Manuals (Repair Group 46).