Measuring The Rear Brake Disc Lateral RUNOUT: Notes

Includes: Measuring the brake disc thickness 

1. Measuring requirement: No tilt play at the wheel.
2. Fit the adapter plate (special tool 9510/1) to the wheel hub. Tightening torque of the wheel bolts (fastening screws) 130 Nm (96 ft.lb).
   Fig 1: Fitting Adapter Plate To Wheel Hub

   Courtesy of PORSCHE OF NORTH AMERICA, INC.
3. Insert dial gauge holder, e.g. Ate order No. 03.9314 - 5500.3/01, into the brake caliper, align it and secure it by turning the clamping wing screw. If the brake disc cannot be turned freely, set the brake pads back a little. Do not damage the spreader spring when fitting the dial gauge holder.
   NOTE:

   • If necessary, provide the dial gauge holder with the Ate conversion set, order No. 03.9314 - 5510.3/01 (longer clamping wing screw and, if necessary, also a bracket for the dial gauge).
4. Secure the dial gauge with some preload. Position the measuring tip outside the perforation on the largest diameter of the braking surface.
   Fig 2: Measuring The Rear Brake Disc Lateral Runout

   Courtesy of PORSCHE OF NORTH AMERICA, INC.
5. Turn the brake disc and, when doing so, read off the lateral runout at the dial gauge. The permissible lateral runout of the installed brake disc is max. 0.06 mm.
   NOTE:

   • Lateral runout of the removed brake disc: max. 0.03 mm.
   • Wheel hub lateral runout: max. 0.03 mm.
6. If the brake disc lateral runout exceeds 0.06 mm, remove the brake disc and check the wheel hub lateral runout. First mark the position with respect to the wheel hub.
7. Check the wheel hub lateral runout as follows: Measure 1 x outside (arrow) and 1 x inside (arrow) of the wheel bolt area (5-point measuring procedure) on the front face of the wheel hub. See Fig 3 . Use a universal dial gauge holder, for example from SNAP - ON (order No. PMF 137), to secure the dial gauge.
   NOTE:

   • The above SNAP - ON order number PMF 137 applies to a complete dial gauge because the dial gauge holder is not available on its own.

   The dial gauge set can also be used to check the brake disc lateral runout.

   Fig 3: Measuring Wheel Hub Lateral Runout (Rear Brake Disc)

   Courtesy of PORSCHE OF NORTH AMERICA, INC.
8. Wheel hub lateral runout too great: Replace the wheel hub. Wheel hub lateral runout in order: Clean the levelling and centering surface on the brake disc and wheel hub. Next, apply a very thin coat of Optimoly TA to the centering surface on the wheel hub. Secure the brake disc to the wheel hub in a different position to the one before and offset radially with respect to the wheel hub. Repeat the measurement with the fitted adapter plate - special tool 9510/1. If the lateral runout is still greater than 0.06 mm, replace the brake disc.