Khớp cầu

A ball joint is a pivoting connection, a ball in a socket, that links steering and suspension parts while allowing movement in several directions.

It lets the wheel steer and the suspension move while keeping the parts connected, much like a hip joint; a worn joint develops play.

Ball joints are used in the steering linkage and suspension arms. Because they affect steering and handling, worn joints should be inspected and replaced by a qualified technician.