Front Disc Rotor: Inspection

Check the front wheel bearing play and axle hub runout before the inspection of disc rotor runout limit. <Ref. INSPECTION , Front 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:

0.075 mm (0.0030 in)

Fig 1: Checking Front 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	24 mm (0.94 in)	22 mm (0.87 in)	294 mm (11.57 in)