In a strut
suspension, the strut assembly usually contains a spring seat to retain the coil
spring that supports the weight of the vehicle. The strut is attached at the
bottom to the lower control arm and at the top to the vehicle body. The upper
connection usually contains a bearing that permits the coil spring to rotate as
the wheels turn, for smoother steering.
The strut suspension has eliminated the need for
several parts, including the upper control arm and the upper ball joint. This
has several advantages including lighter suspension weight, fewer moving parts
and more room in the engine compartment.