Checking Lateral Runout (Brake Disc/Wheel Hub) And Thickness Tolerance

Information 

Fasten dial gauge set with ball joint arm to wheel bearing housing.

Two adapters are used for checking lateral runout. The brake disc and wheel hub can be measured with these.

Brake disc lateral runout

1. Remove the wheel → WM 440519 REMOVING AND INSTALLING WHEEL and fit the adapter plate 9510/1  with tightening torque 160 Nm (118 ftlb.).
   Fig 1: Identifying Adapter Plate On Wheel Hub

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
2. Fit the adapter dial gauge set with ball joint arm Nr.147-1  at a suitable position on the wheel bearing housing (schematic representation of front axle).
   Fig 2: Fitting Dial Gauge On Brake Disc

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
3. Fit the dial gauge with some preload and measure the lateral runout at the greatest external diameter of the brake disc.

Wheel hub lateral runout

Information 

The front face of the wheel hub must not be corroded. If necessary, clean with fine emery cloth.

• Measure the wheel hub lateral runout at the front face of the wheel hub. You should always measure the external and internal diameters of the wheel bolt area.

1. Remove the brake disc. → 465319 REMOVING AND INSTALLING REAR BRAKE DISC 
2. Fit the adapter dial gauge set with ball joint arm Nr.147-1  at a suitable position on the wheel bearing housing (schematic representation of front axle). Fit the dial gauge with some preload.
   Fig 3: Fitting Dial Gauge On Wheel Hub

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Brake disc thickness tolerance

• For details of brake disc thickness tolerance, see Technical data/brake wear limits. → WM 4600TW TECHNICAL DATA/TEST VALUES AND BRAKE WEAR LIMITS 
• Measure the thickness tolerance with a suitable micrometer screw within the braking surface at approx. 8 points.