What are Idler Arms?
When you turn the steering wheel, there must be some way to convert that rotary motion to linear motion, that is, to push and pull the front wheels to the left and to the right. In older vehicles through the 1980s and some light SUVs and heavy SUVs and trucks through today, this is accomplished via a recirculating-ball steering gear. The steering gear converts a lot of your rotary motion into a tiny rotary motion, moving the pitman arm through and arc of maybe 60°. It’s not exactly linear, but it’s close enough for the rest of the steering linkage, tie rods, and idler arms. (On almost all vehicles since the 1990s, recirculating ball steering has been replaced by a truly rotary-to-linear solution, the rack and pinion.)
As the steering gear turns the pitman arm, the pitman arm pushes the track rod to the left or right, depending on which way the driver is turning the steering wheel. Because the suspension and steering allows for movement, both up and down and turning left and right, the steering linkage is composed of several pieces, connected by flexible joints. Fixed at the steering knuckles and at the pitman arm, the right side of the track rod would simply drop if it was not supported. Also, the unsupported track road would simply buckle if attempting to turn the right wheel. The idler arm’s job is to hold up the right side of the track rod.
Why are Idler Arms Important?
Idler arms are particularly important for two reasons. First, as mentioned, the idler arm supports the right end of the track rod. Without it, the track rod would not hold the right wheel in place or turn it effectively, if at all.
Second, the idler arm maintains proper toe angle. Idler arms feature two joints, usually a small ball-and-socket joint on the track rod and a rotating joint fixed to the vehicle frame. This allows for movement only on a short arc, the same as the pitman arm. If the ball joint or rotating joint wears out, it could allow for movement, which would skew alignment angles and cause vehicle drifting, pulling, or abnormal right front tire wear.
What can Dobbs Tire & Auto Centers Do for You?
Trusted tire, suspension, and steering specialists have been maintaining cars, trucks, and SUVs in St. Louis for over forty years. Today, with 43 locations in the area, a competent steering system check is closer than you might think. From yesterday’s classics to modern heavy-duty trucks and off-road vehicles, idler arms and tie rod ends are well within the realm of our ASE-certified technicians’ expertise. If you’re experiencing drifting, pulling, or abnormal tire wear, you owe it to your vehicle to have it checked by the experts at Dobbs Tire & Auto Centers.
“You Can Depend on Dobbs” – Dobbs Tire & Auto Centers, Home of the Fixed Forever Service Warranty. Locally and Family Owned Since 1976