172 Auto Suspension and Steering
Column Design
The steering column is the support and cover for the
steering shaft and other steering wheel–mounted
components and wiring. Shaft bearings are ball or roller
bearings installed at the top and bottom of the steering
column to allow the steering shaft to turn with no resist-
ance. The steering column is attached to the underside of
the dashboard, usually through studs and nuts. Many of
the column attachment holes are slotted to allow for
steering column adjustment. On some vehicles, the bottom
of the column is attached to the firewall.
The upper part of the steering column is usually
somewhat larger in diameter to hold the driver-operated
components, as well as the air bag clockspring. The
steering column usually contains the turn signal indicator
stalk, Figure 9-9. In addition to controlling the turn signals,
the modern turn signal stalk may also be used to operate
the cruise control, the windshield wipers, and the high-
beam selector.
On most modern vehicles, the ignition switch is
installed inside the steering column. The ignition lock
assembly is installed on the column and connected to the
switch by a metal rod. On some vehicles, the steering
column contains the gearshift indicator and selector lever.
Neutral safety switches and vacuum parking brake release
switches may also be located on the lower portion of the
steering column.
The steering column is collapsible, although its design
is somewhat different from that of the steering shaft. The
lower section of the steering column is perforated and
resembles a heavy screen, Figure 9-10. If the driver hits the
steering wheel during an accident, the perforated area will
bend, allowing the column to collapse.
Universal
joint
Lower steering shaft
Upper
steering shaft
Column
assembly
Figure 9-8. This steering shaft assembly uses a universal joint.
(Toyota)
Steering
column
Cover
Turn signal
indicator
stalk
Cruise control
wire connections
Figure 9-9. Cutaway view of a steering column showing the turn
signal stock (lever) assembly. Stock assemblies vary in function,
shape, etc. (General Motors)
Perforated section of
steering column
Position
arm
PRNDL cable
Adjustable Steering Columns
Some steering columns can be adjusted to change the
position of the steering wheel. Adjustable steering
columns make driving more comfortable for people who
are shorter or taller than average. Changing the wheel posi-
tion can also make long trips more comfortable.
On a tilt steering wheel, the steering column is
sectioned at the top and can pivot. The upper part of the
steering shaft is equipped with a universal joint. There may
be an extra bearing at the tilt mechanism to further support
the shaft. A lock holds the steering column in position as
the vehicle is driven. A lever mounted on the steering
column releases the lock when the driver wants to change
the steering wheel position. The design of a typical tilt
steering column is shown in Figure 9-11.
Telescoping steering columns are designed so that the
steering wheel can be moved either toward or away from
the driver. The telescoping parts of a steering column
include a solid steering shaft section inside a hollow shaft
section. This assembly is called a telescopic shaft. During
normal driving, a locking mechanism holds the telescopic
shaft in position. Moving a lever on the steering column
allows the driver to release the lock and move the steering
wheel. When the lever is released, the column is locked in
the new position. See Figure 9-12.
Figure 9-10. This collapsible steering column has a perforated
steering column tube. (Chrysler)