A - Frame and Suspension Fundamentals

Question 1

List three functions of a vehicle frame.

Answer 1

Provide a platform on which the major vehicle components are attached, support the load that the vehicle intended to carry, and resist shock and torsional loads when the vehicle is in operation.

Question 2

The point at which the maximum force is concentrated on a frame is called the:

Answer 2

Maximum bending moment.

Question 3

A ladder type frame is made up of:

Answer 3

Parallel frame rails and cross members.

Question 4

The function of frame cross members is to:

Answer 4

Provide strength and rigidity to the frame assembly.

Question 5

Which one of the following is not a common frame rail shape: Trapezoid, channel, box, or I-beam.

Answer 5

Trapezoid.

Question 6

The surface between the flanges of an I-beam frame rail is called the:

Answer 6

Web.

Question 7

What is the function of a gusset that is attached to a frame cross member?

Answer 7

Gussets provide resistance to frame weaving.

Question 8

True or False: The size and shape of frame components affects the strength of the frame.

Answer 8

True.

Question 9

Define the term Yield Strength as it applies to the strength of frame materials.

Answer 9

Yield strength refers to the amount of stress that the material can withstand before becoming permanently deformed.

Question 10

Which of the following frame materials would have the highest yield strength: Mild steel, High strength, low alloy steel, heat-treated alloy steel, or copper-aluminum alloy.

Answer 10

Heat-treated alloy steel.

Question 11

The term Section Modulus refers to the strength of frame components based on:

Answer 11

Height, width, thickness, and shape.

Question 12

True or False: A frame with a high resisting bending moment (RBM) has less strength than a frame with a low RBM.

Answer 12

False, The greater the RBM, the greater the strength of the frame.

Question 13

List four functions of a vehicle suspension system.

Answer 13

Secure the axles to the frame while maintaining proper alignment, Support the weight of the vehicle and its cargo while maintaining lateral stability, Cushion shock loads, and Allow axle movement so that the tires follow the contour of the road.

Question 14

True or False: The term Unsprung Weight refers to the weight of the vehicle and its load.

Answer 14

False, The combined weight of the components below the connection point is called unsprung weight because it is located below the suspension system.

Question 15

The suspension system must hold the axles in alignment with the frame. This means that the:

Answer 15

Wheels are held parallel to the frame rails.

Question 16

Three of the most common types of energy-absorbing devices used in suspension systems are:

Answer 16

Leaf spring, rubber cushion, rubber air spring.

Question 17

True or False: The energy-absorbing device of a suspension system is released when it rebounds.

Answer 17

True.

Question 18

Solid-mount suspension systems are best suited to applications that:

Answer 18

Operate on rugged terrain.

Question 19

Equalizer beams reduce the effect of shock loads to the frame by:

Answer 19

50%

Question 20

Axles are stabilized against braking and acceleration forces by:

Answer 20

Longitudinal torque rods.

Question 21

The function of transverse torque rods is to:

Answer 21

Provide improved side-to-side stability by distributing side loads more evenly across the entire length of the axle.

Question 22

True or False: Progressive leaf springs provide a load spring rate when the vehicle is unloaded and a high spring rate under load.

Answer 22

True.

Question 23

Auxiliary springs help to support the vehicle when it is:

Answer 23

Loaded.

Question 24

True or False: Spring shackles accommodate changes in spring length as the suspension jounces and rebounds.

Answer 24

True.

Question 25

The main function of a shock absorber is to:

Answer 25

Dampen spring oscillation.

Question 26

The function of vertical drive pins on a rubber cushion type suspension is to:

Answer 26

Allow the saddles to move up and down as the load cushions deflect, thus maintaining alignment of the saddles with the frame rails.

Question 27

An advantage that air spring suspensions have over other suspension types is that they provide superior:

Answer 27

Ride quality.

Question 28

State the function of the pressure protection valve in an air spring suspension.

Answer 28

Ensures that a minimum safe pressure is maintained in the air reservoir for air brake operation if a leak occurs in the suspension air system.

Question 29

The ride height control valve supplies air to the air springs when:

Answer 29

Additional load is added to the vehicle.

Question 30

The function of the two-way control valve and dump valves is to:

Answer 30

Allow the driver to exhaust the air springs so that the suspension will lower when connecting or disconnecting a trailer.