Front Bushing

Set the ST A with the larger side of its inner diameter turned upward.
Set the rear arm with the vehicle inner side of arm turned downward.
Place the bushing on rear arm as shown in the figure.
Place the ST B on the bushing, and press-fit until each edge surface of bushing and rear arm is aligned.
ST A 20099AE020 INSTALLER & REMOVER SET

ST B 20099AE020 INSTALLER & REMOVER SET

Fig 1: Pressing Bushing Into Trailing Link Using Installer
Courtesy of SUBARU OF AMERICA, INC.