Auto Service World
Feature   September 1, 2002   by CARS Magazine

Chassis Service: Simple, But Important

Pinch bolt retention of ball joints is effective, but improper service procedures can cause hub damage...or separation

Lower ball joints on many Macpherson strut vehicles are retained by a split ear hub mounting using a pinch bolt passing through a slot or groove in the ball stud.

After removing the nut, the pinch bolt should be easily removed by pushing on it with your finger. If the bolt cannot be removed by finger pressure, pry down on the control arm until the bolt moves freely. Some pinch bolts are serrated. Tap on bolt to bread loose. Most of the same procedures can be followed for installation of the pinch bolt.

Some ball joint studs have only a slot where the pinch bolt rests, while others have a groove around the entire stud. If separating the ball joint stud from the steering knuckle is difficult, put penetrating oil in knuckle groove and rotate knuckle on stud to extremes several times.

Note: Beating on the pinch bolt can cause damage to the bolt and ball joint. The slit in the steering knuckle must NOT be widened with a chisel or other tool.

Inspect ball joint flange of steering knuckle and remove any dirt from holes in flange. If ball joint stud was loose or broken, if any out of roundness or damage is noted to holes, or if excessive deformation of flange is noted, the steering knuckle must be replaced. Failure to replace a damaged, deformed, or worn knuckle may cause loss of steering ability since the ball joint stud or pinch bolt may break and cause separation.

The steering knuckle must be replaced if dimension “A” minus dimension “B” is .032 or more before clamping. Steering knuckle must be replaced if any test indicates an out of round ball joint stud hole.

Information courtesy of Federal-Mogul Corporation – Moog Chassis Parts ServiceLink