Rear Control Arm Bushing Set by Energy Suspension®. Energy Suspension lets you upgrade worn and crumbling rubber bushings that dampen vibrations at mounting points for front upper and lower control arms, rear upper and lower control arms, rear trailing arms, and track arms. Resilient polyurethane construction offers greater resistance to deterioration from road grime, oil leaks, and salt slush without drying out or crumbling the way rubber mounts can.