For American Cars 1939-1991DO IT ONCE and DO IT RIGHT! ® with an idler arm for your car's steering system! The Idler Arm is essential to proper steering control and response, as it adds stability to the center link and tie rod assembly. As the Idler Arm wears, undesirable up and down movement in the steering assembly will translate into free play or looseness at the steering wheel. Replace your Idler arm & improve your car's handling.