92 Auto Suspension and Steering
Torsion Bar Suspension
Torsion bar suspensions have been used on many
passenger cars in the past and are used on many current
front- and four-wheel drive vehicles to eliminate clearance
problems between the spring and drive components. On
most torsion bar suspensions, the bar is connected to the
lower control arm. In some cases, the torsion bar is
connected to the control arm through an adjuster lever and
bolt, Figure 5-19, with the opposite end of the bar
connected to a fixed mounting point on the vehicle’s
frame. In other systems, the bar is mounted to the frame
through an adjuster lever and bolt, with the fixed mounting
on the control arm. See Figure 5-20.
The fixed mounting point for the torsion bar consists
of an opening that corresponds to the end torsion bar end.
See Figure 5-21. This provides a strong mounting point
while allowing some back-and-forth movement when the
suspension is stressed.
In some cases, the torsion bar is mounted directly to
the control arm at the pivot point. On a few systems,
the torsion bar is connected to the upper control arm,
Figure 5-22.
Some vehicles have a transverse torsion bar arrange-
ment, which is shown in Figure 5-23. This torsion bar
arrangement is no longer used, but it may be encountered
on some older cars.
Shock
absorber
Lower
arm
Upper
arm
(wishbone)
Steering
knuckle
Strut bar
Stabilizer bar
Coil spring
Figure 5-13. A double wishbone, independent front suspension
system. (Lexus)
Multilink
assembly
Strut rod
Figure 5-14. A multilink front suspension. (Moog)
Short
arm
Long
arm
A
Compression
At-rest position
Rebound
Compression
At-rest position
Rebound
B
Figure 5-15. A—Conventional front suspension using short and
long arms. B—Suspension action. (Ford)