cracks in the frame side rails. Care should be exercised
when performing this task, as the frame can be
weakened. The frame of the vehicle should not be
welded by gas or arc welding unless specified by the
manufacturer. The heat removes temper from the
metal, and, if cooled too quickly, causes the metal to
crystallize. Minor bends can be removed by the use of
hydraulic jacks, bars, and clamps.
REVIEW 1 QUESTIONS
What component of the frame prevents the side
members from weaving and twisting the frame?
The integrated frame and body type of
construction is also known by what term?
One advantage of an integrated frame and body
is that the amount of noise transmitted into the
passenger compartment is decreased. (T/F)
Figure 8-4.Truck frame (Ladder).
Provide a smooth, comfortable ride by allowing
the wheels and tires to move up and down with
minimum movement of the vehicle.
Work with the steering system to help keep the
wheels in correct alignment.
Keep the tires in firm contact with the road, even
after striking bumps or holes in the road.
Allow rapid cornering without extreme body roll
(vehicle leans to one side).
Allow the front wheels to turn from side to side
Prevent excessive body squat (body tilts down in
rear) when accelerating or with heavy loads.
Prevent excessive body dive (body tilts down in
the front) when braking.
The suspension systems are grouped into two
categories, which are as follows:
Learning Objective: Identify automotive suspension
components, their functions, and maintenance
The suspension system works with the tires. frame
or unitized body, wheels, wheel bearings, brake
system. and steering system. All of the components of
these systems work together to provide a safe and
comfortable means of transportation. The suspension
system functions are as follows:
NONINDEPENDENT SUSPENSION (Solid
Axle) (fig. 8-5)The nonindependent suspension has
both left and right wheels attached to the same solid
axle. When one tire hits a bump in the road, its upward
movement causes a slight tilt in the other wheel. With a
solid axle setup, the steering knuckle and wheel spindle
assemblies are connected to the axle beam by
bronze-bushed kingpins, or spindle bolts, which
provide pivot points for each wheel.
Support the weight of the frame, body, engine,
transmission, drive train, passengers, and cargo.
INDEPENDENT SUSPENSION (fig. 8-6)The
independent suspension allows one wheel to move up
and down with a minimum effect on the other wheels.
Since each wheel is attached to its own suspension unit,
movement of one wheel does NOT cause direct
movement of the wheel on the opposite side of the