Front Suspension Ball Joint

Lift up the vehicle until front wheels are off ground.
Grasp the bottom of tire and move it in and out in axial direction. If movement (B) is observed between the brake disc cover (A) and end of front arm (D), ball joint (C) may be excessively worn.

Fig 1: Identifying Movement Between Brake Disc Cover And End Of Front Arm
Courtesy of SUBARU OF AMERICA, INC.
Next, grasp the end of front arm (C) and move it up and down. If movement (A) between the housing (D) and front arm (C) boss is observed, ball joint (B) may be excessively worn.

Fig 2: Identifying Movement Between Housing And Front Arm
Courtesy of SUBARU OF AMERICA, INC.
If the relative movement is observed in the preceding two steps, remove and inspect the ball joint. If the free play exceeds standard value, replace the ball joint. Refer to FRONT BALL JOINT FS-31, Front Ball Joint.
Damage of dust boot
Visually inspect the ball joint dust boot. Replace if ball joint is damaged.

NOTE: When the front arm ball joint is removed or replaced, check the toe-in of front wheel. If it is not within the specified value, adjust the toe-in. Refer to WHEEL ALIGNMENT FS-9, Wheel Alignment.

Fig 3: Identifying Dust Boot
Courtesy of SUBARU OF AMERICA, INC.