Rear Disc Rotor: Inspection

WARNING: This page is about a different car, the 2011 Subaru Tribeca. However, it is still accessible from the selected car via links, so may be relevant.

Check the rear wheel bearing play and axle hub runout before inspecting the disc rotor runout limit. Refer to REAR HUB UNIT BEARING INSPECTION, Rear Hub Unit Bearing.
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).

Fig 1: Checking Disc Rotor Runout
Courtesy of SUBARU OF AMERICA, INC.

Disc rotor runout limit:

0.05 mm (0.0020 in)
Set a micrometer 10 mm (0.39 in) inward from the 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: Locating Threaded Section (B) Of Disc Rotor

Courtesy of SUBARU OF AMERICA, INC.

	Specification	Service limit	Disc rotor outer diameter
Disc rotor thickness A mm (in)	18 (0.71)	16 (0.63)	320 (12.59)