Section 8 (Starting System & Charging System (H4DO)): Starter: Inspection: Armature

WARNING: This page is about a different car, the 2013 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.

Check the commutator for signs of seizure or stepped wear caused by roughness of the surface. If there is light wear, use sandpaper to repair.
Check for runout on the commutator. If excessive, replace the armature.
Commutator runout:

Standard

0.05 mm (0.0020 in)

Limit

0.10 mm (0.0039 in)

Fig 1: Checking Commutator Runout
Courtesy of SUBARU OF AMERICA, INC.
Check the depth of the segment mold. If it is not within the standard, replace the armature.
Depth of segment mold:

Standard

0.50 mm (0.020 in)

Fig 2: Identifying Depth Of Segment Mold
Courtesy of SUBARU OF AMERICA, INC.
Place the armature on the growler tester to check for short circuits. While slowly turning the armature, support the steel sheet for the armature core. If the circuit of the armature is shorted, the steel sheet will vibrate, causing it to move towards the core. When the steel sheet has moved or vibrated, replace the armature.

Fig 3: Checking Armature For Short Circuits On Growler Tester
Courtesy of SUBARU OF AMERICA, INC.
Use a circuit tester to touch the probe of one side to the commutator segment, and the other probe to the shaft. If there is continuity, replace the armature.

Fig 4: Checking Armature Continuity Using Circuit Tester
Courtesy of SUBARU OF AMERICA, INC.