Chapter 5 Front Suspension Systems 91
lower arm. This causes the wheel to move upward in an
arc. Moving the wheel up and down in an arc keeps the
entire tire tread in contact with the road. See Figure 5-15.
Conventional Suspension Variations
The major differences between conventional front
suspensions are whether springs or torsion bars are used,
and whether they are installed on the upper or lower con-
trol arm. These differences are discussed in the following
sections.
Coil Spring Suspension
On most late-model conventional suspensions, the
coil spring is installed between the lower control arm and
the frame, Figure 5-16. On most cars, the shock absorber
is installed inside of the spring. Rubber or neoprene bum-
pers, Figure 5-17, installed on the frame or control arms
prevent damage to other suspension parts if the suspension
bottoms out.
On some conventional suspensions, the coil spring is
installed between the upper control arm and the vehicle
body, as shown in Figure 5-18. The shock absorber is
mounted inside the spring.
Nut
Nut
Upper
link
bracket
Upper
link
Third link
Wheel hub
and steering
knuckle assembly
Nut
Nut
Transverse link assembly
Tension rod
Tension rod
bracket
Bolt
Front stabilizer
Front suspension member
Shock absorber
Coil spring
Shock absorber
mounting insulator
Front
Figure 5-11. One particular MacPherson front suspension layout, showing some of the various parts. (Nissan)
Strut
Coil spring
Figure 5-12. In a modified MacPherson strut suspension, the
spring is mounted separately from the strut. (Perfect Circle)