Deck 26: Suspension Systems

Question 1

What enables a variable-rate,multi-leaf spring to become progressively stiffer as weight is added to a frame?

A) cam brackets make contact close to the center of the spring as it deflects
B) the ends of lower leaves in the spring pack come into contact with the upper leaves
C) both A and B
D) neither A nor B

Answer 1

C

Question 2

When load is added to a truck with a pneumatic suspension,in which direction should the height control valve lever move?

A) downward
B) upward
C) horizontally
D) stays stationary

Answer 2

B

Question 3

Which of the following causes could account for frequent leaf spring breakage?

A) vehicle overloaded
B) insufficient torque on the U-bolt nuts
C) broken centerbolt
D) all of the above

Answer 3

D

Question 4

Which type of air spring is most commonly used in heavy-duty trucks?

A) single-convoluted
B) double-convoluted
C) triple-convoluted
D) reversible sleeve

Question 5

When a truck suspension is overloaded,what other areas of the truck can also be damaged?

A) frame
B) axles
C) tires
D) all of the above

Question 6

Which of the following is NOT a function of the alignment clips on a multi-leaf suspension?

A) limit sideways spread
B) position the axle
C) limit vertical separation
D) all of the above

Question 7

Which of the following best describes how driving,braking,and cornering forces are transmitted to the frame on a truck is equipped with rubber load cushion-type equalizing beams?

A) transmitted directly through the rubber cushions to the frame brackets
B) transmitted through rubber-bushed vertical drive pins in each cushion
C) torque rods transmit 100% of these forces
D) equalizing beams transmit 100% of these forces

Question 8

When an air suspension system height control valve lever is in its neutral position,how should it be positioned?

A) parallel with frame
B) 45-degrees upward from level
C) 45-degrees downward from level
D) vertical to frame

Question 9

When 20,000 pounds (9072 kg)is loaded onto the frame of a truck it lowers by one-inch (25 mm).However,another 30,000 pounds (13,608 kg)has to be added before it lowers another inch (25 mm).Which of the following types of suspension is this truck likely to have?

A) pneumatic
B) standard leaf spring
C) progressive leaf spring
D) equalizing-beam

Question 10

When a truck with a pneumatic suspension travels over a bumpy surface,what prevents the height control valve from rapidly cycling (inflating/exhausting)in response to each bump?

A) built in response delay mechanism
B) compressibility of air in springs dampens rapid changes in pressure
C) both A and B
D) neither A nor B

Question 11

When should the U-bolts on a spring suspension be re-torqued after installation?

A) after the first 1,000 miles (1,600 km)
B) after 36,000 miles (58,000 km)
C) after one year
D) they should not be touched after torque is set

Question 12

What is the function of the centerbolt in a multi-leaf spring pack?

A) acts as a locating dowel to position the axle
B) clamps the spring leaves together
C) its tension helps define the spring pack self-dampening properties
D) all of the above

Question 13

Which of the following means the same thing as equalizing-beam suspension?

A) torsion bar
B) walking beam
C) air spring
D) multi-leaf variable rate

Question 14

Which of the following functions can be performed by torque rods?

A) dampen axle windup caused by driveline torque
B) align axles
C) dampen axle twist under braking
D) all of the above

Question 15

Which of the following suspension components is NOT usually found in heavy-duty trucks or trailers today?

A) multi-leaf springs
B) coiled springs
C) air springs
D) equalizing-beam

Question 16

Which of the following suspension system components play a role in positioning an axle?

A) torque rods
B) centerbolts
C) torque leafs
D) all of the above

Question 17

Which of the following are advantages of using fiber-composite leaf springs?

A) reduced unsprung weight
B) quieter ride
C) less spring sag tendency
D) all of the above

Question 18

Which of the following is NOT an indication of worn-out,front axle shock absorbers?

A) excessive spring oscillations
B) reduced suspension height
C) front wheel shimmy
D) excessive tire wear

Question 19

What is the reason for coating steel components with a special compound when they contact with an aluminum frame?

A) prevents corrosion
B) limits squeaks and rattles
C) reduce harshness in the suspension system
D) all of the above

Question 20

Which of the following suspension systems will NOT usually be used as a front axle,truck suspension?

A) equalizing-beam
B) camelback
C) solid rubber block
D) all of the above

Question 21

When reinstalling rubber-bushed equalizing beams,what do you have to do before torquing the nuts to specification?

A) install the torque rods
B) ensure the equalizing beams are parallel to the frame
C) both A and B
D) neither A nor B

Question 22

If you were to paint the leaf springs when assembling a multi-leaf spring pack,which of the following spring characteristics would be compromised?

A) maximum load rating
B) no-load ride
C) jounce properties
D) inter-leaf friction

Question 23

What is the air pressure regulated at on a typical truck or trailer air suspension?

A) 60 psi (4.1 bar)
B) 90 psi (6.2 bar)
C) 125 psi (8.6 bar)
D) chassis system pressure

Question 24

What is usually used to mount a multi-leaf spring pack to an axle saddle?

A) centerbolt
B) spring clips
C) spring shackles
D) U-bolts

Question 25

Which of the following would best describe a multi-leaf steel spring pack used in a truck or trailer application?

A) diamond-shaped
B) semi-elliptical
C) cylindrical
D) elliptical

Question 26

A truck with a steel multi-leaf spring,front suspension undergoes prolonged bouncing after hitting a bump in the road.Technician A says this could be caused by defective shock absorbers.Technician B says this could be caused by a broken centerbolt.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 27

When a truck pneumatic air suspension height control valve lever moves downward off horizontal,what happens to the air in the air springs?

A) more air is charged to the springs
B) some air is exhausted from the springs
C) all of the air is dumped
D) inflated to chassis system pressure

Question 28

All of the weight NOT supported by a vehicle suspension is known as:

A) gross vehicle weight
B) gross load
C) sprung weight
D) unsprung weight

Question 29

What is meant by the term adaptive suspension when used in the context of a truck or trailer?

A) adjusts to chassis load conditions automatically
B) enables quick suspension component change-outs
C) combines steel and air springs
D) ride height adapts to actual road speed

Question 30

Which of the following suspension components has good self-dampening spring oscillation characteristics?

A) air springs
B) coil springs
C) multi-leaf spring packs
D) all of the above

Question 31

Technician A says that chassis oscillations can be rhythmic vibrations sourced from the suspension.Technician B says that chassis oscillations can be irregular vibrations sourced from the suspension.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 32

What type of forces are easily absorbed by an air spring?

A) longitudinal forces
B) vertically applied forces
C) transverse forces
D) both A and C

Question 33

What is the most compressed condition of a spring known as?

A) rebound
B) jounce
C) unsprung
D) sprung

Question 34

What is the function of a torque rod used with a equalizer type,multi-leaf spring pack,tandem suspension?

A) controls longitudinal forces
B) dampens axle wind-up caused by braking forces
C) dampens axle wind-up caused by acceleration forces
D) all of the above

Question 35

After being subject to jounce,what is a spring likely to do?

A) rebound
B) break
C) rejounce
D) compress

Question 36

Technician A says that the cam brackets used in a variable rate spring are only in contact with the mainleaf when the chassis is unloaded.Technician B says that cam brackets are used to shorten the effective spring length when in contact with the mainleaf.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 37

Which of the following suspension components is used specifically to dampen oscillation frequency?

A) coil springs
B) air springs
C) shock absorbers
D) spring shackles

Question 38

In a truck front suspension in which the spring is fixed at one end by pin,which of the following components permits variations in spring length as the spring flexes?

A) mainspring eye
B) rebound clips
C) U-bolts
D) spring shackles

Question 39

In a reversible sleeve type air spring,what prevents frame-to-piston contact when the air spring is subjected to extreme jounce?

A) air supply port
B) shock absorber
C) jounce block
D) torque rod

Question 40

Technician A says that it is desirable to keep vehicle unsprung weight as heavy as possible because it makes for a more gentle ride.Technician B says that unsprung weight has a reaction effect through the suspension and frame.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 41

Which of the following explains why you have to hold some types of air suspension height control valves in an off-horizontal position for up to 15 seconds before it responds to the movement?

A) valve is defective
B) cold weather operation
C) hydraulic reaction delay
D) pneumatic-actuated reaction delay

Question 42

When a truck chassis is equipped with a rollover stability control (RSC)system,which data bus electronic system is it usually integrated with?

A) engine controller
B) chassis controller
C) transmission controller
D) ABS/ATC controller

Question 43

Which of the following shop tools would most likely be required to remove old rubber bushings from an equalizing beam type suspension?

A) hammer and chisel
B) oxy-acetylene cutting torch
C) rosebud
D) 50-ton hydraulic press

Question 44

Technician A says that an RSC system can request over the chassis data bus a reduction of engine torque.Technician B says that a driveline retarder can be actuated as a result of a RSC request over the data bus.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 45

Which of the following is a notably reliable tattletale of suspension problems before they result in a complete failure?

A) driver complaints
B) tire wear patterns
C) cracks in frame
D) increased air compressor cycling

Question 46

Technician A says that when installing a multi-leaf spring pack,the U-bolts should be torqued over the axle saddle before connecting the spring pin.Technician B says that the weight should be off the spring before torquing a U-bolt.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 47

Technician A says that body-bound bolts used in some suspensions are almost always SAE Grade 5 rated because they need to flex.Technician B says that it is generally safe to replace Huck fasteners used to mount suspension components with SAE Grade 5 fasteners.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 48

Which of the following is the least recommended method of checking axle alignment on a truck or trailer?

A) tram gauge and straight-edge
B) light and laser beam alignment
C) computer controlled sensor systems
D) all have equal accuracy

Question 49

While lubricating a rear suspension with an air-actuated grease gun,one spring pin will not take grease.Which of the following should be done first?

A) remove weight from suspension and try with a hand grease gun
B) heat the spring with a rosebud
C) remove weight from the suspension and hammer on eye while pumping grease
D) replace the mainleaf

Question 50

A multi-leaf spring pack on a truck front suspension has a single broken leaf.If you observe what the OEM recommends,which of the following would be correct procedure?

A) rebuild the spring pack,replacing the broken leaf
B) replace the spring pack with the broken leaf with a new spring pack
C) replace both front axle spring packs
D) replace all springs on the vehicle,front and rear