Disc Rotor RUNOUT Check

WARNING: This page is about a different car, the 2021 Subaru Ascent. However, it is still accessible from the selected car via links, so may be relevant.

Check the front hub unit bearing for free play and runout before the inspection of brake disc front runout limit. Ref. to PROPELLER SHAFT/DRIVE SHAFT/AXLE>Front Hub Unit Bearing>INSPECTION .

Check the brake disc front runout.

Remove the caliper body. Ref. to BRAKE>Front Disc Brake Assembly>REMOVAL .
Secure the brake disc front by tightening the five wheel nuts.

Set a dial gauge 10 mm (0.39 in) inward from the brake disc front outer circumference, and check the runout of front side while rotating the brake disc front.

Preparation tool:

Dial gauge

Magnet stand

Brake disc front runout limit

0.05 mm (0.002 in)

NOTE: < Example of magnet stand and dial gauge installation>
The location where the magnet stand is installed varies to stabilize the magnet stand.

Courtesy of SUBARU OF AMERICA, INC.

Set a dial gauge 10 mm (0.39 in) inward from the brake disc front outer circumference, and check the runout of backside while rotating the brake disc front.
Preparation tool:

Dial gauge

Magnet stand

Brake disc front runout limit

0.05 mm (0.002 in)

NOTE: < Example of magnet stand and dial gauge installation>
The location where the magnet stand is installed varies to stabilize the magnet stand.

Courtesy of SUBARU OF AMERICA, INC.

If the brake disc front runout exceeds service limit, grind the brake disc front.
Check the brake disc front thickness after grinding. Ref. to BRAKE>Front Disc Rotor>INSPECTION> DISC ROTOR THICKNESS CHECK .