Arm. Radius.
A suspension Arm used to control wheel motion in the longitudinal or transverse direction. It is connected on one end to the wheel carrier or axles, and on the other end to the chassis or frame of the vehicle. Adjustment. Rod. Alignment Pinion Angle. Torque.

Radius Arm

Fits E-150, E-250, E-350 Super Duty, E-450 Super Duty

E-350 Super Duty; Right. E-450 Super Duty; Right. E150-350 Vans; Right.
Radius Arm - Repair or Replace
If you hear a clunk or pop when going over bumps or when applying the brakes or accelerating, your Ford E-250 Econoline may need to have the radius arm or its bushings examined. A bent or otherwise damaged control arm can also cause your vehicle to pull to one side.