Rear Disc Rotor: Inspection

Check the rear wheel bearing play and axle hub runout before the inspection of disc rotor runout. <Ref. INSPECTION , Rear Axle. >
Secure the disc rotor by tightening the five wheel nuts.
Set a dial gauge 10 mm (0.39 in) inward from the disc rotor outer circumference. Rotate the disc rotor to check runout. If the disc rotor runout exceeds the limit, resurface the disc rotor. After resurfacing, check disc rotor thickness as in step 4).
Disc rotor runout limit:

0.070 mm (0.0027 in)

Fig 1: Checking Rear Wheel Bearing Play And Axle Hub
Courtesy of SUBARU OF AMERICA, INC.

Set a micrometer in 10 mm (0.39 in) inward from disc rotor outer perimeter, and then measure the disc rotor thickness. If the thickness of disc rotor exceeds the service limit, replace with a new disc rotor.

Fig 2: Identifying Disc Rotor Thickness

Courtesy of SUBARU OF AMERICA, INC.

THICKNESS SPECIFICATION

Standard		Limit	Disc rotor outer dia.
Disc rotor thickness A	10 mm (0.39 in)	8.5 mm (0.335 in)	266 mm (10.47 in)