An air spring and a linear guide are used to boost the effectiveness of a
leaf spring suspension system for a motor vehicle. The air spring mounts
between the axle and the vehicle frame. The aft end of the leaf spring
mounts to the linear guide to allow the leaf spring to move vertically as
well as front and back while restricting side-to-side movement. The air
spring and linear guide can be added during vehicle assembly or afterward
from an aftermarket kit of parts.