Ball Joints

A ball joint is the pivoting connection between the suspension arm and the wheel hub. It allows the wheel to steer and to move up and down while keeping it located.

What it does

A ball and socket enclosed in a grease-filled rubber boot carries vehicle weight while permitting movement in several planes. The boot keeps grease in and water and grit out.

Signs a ball joint is failing

A knocking from the front over bumps or on turning
Vague steering or a wandering feel at speed
Uneven tyre wear on the inner or outer shoulder
A split or perished boot with grease thrown around the area
Play felt when the wheel is rocked with the vehicle raised

When to replace them

Not scheduled. Replaced when play develops or when the boot has split and grease has been lost. A split boot means failure is coming even if there is no play yet.

What to confirm before ordering

Have these ready and the counter can usually confirm the part in under a minute.

Upper or lower joint, and left or right
Whether it is supplied separately or only with a complete arm
Taper size and thread
That alignment is booked for after fitting

Ball Joints by vehicle

Pick your vehicle for the years and engines covered, and what is specific to that application.

Ball Joints questions

What happens if a ball joint fails completely?

The suspension arm separates from the hub and the wheel collapses inward. It is one of the few suspension failures that causes immediate loss of control, which is why any detected play should be dealt with promptly.

Does a split boot mean the joint needs replacing?

In practice yes. Once the boot splits, grease escapes and water and grit enter. The joint may still feel tight, but its life is now short.