Front Track Arm Bushings (4.7131R) by Energy Suspension. Red. This is a set of replacement polyurethane bushings designed to exceed factory OEM levels of strength and flexibility at the pivot points where your rear track arms (or Panhard arms) attach to the axle of the vehicle to prevent sideways movement of individual wheels. 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.