401A: Clutch Fundamentals and Service

Question 1

Spring loaded clutches have three styles of spring, what are they?

Answer 1

Perpendicular, diaphragm and angle

Question 2

What are the two types of spring clutches?

Answer 2

Push and Pull type

Question 3

When the operator pushes the clutch pedal to the floorboard, is the clutch engaged or disengaged?

Answer 3

Disengaged

Question 4

The springs in the clutch are naturally in the engage or disengaged position?

Answer 4

Engaged

Question 5

Where are the pressure springs usually located?

Answer 5

Between the clutch cover and pressure plate

Question 6

When a spring-loaded clutch is engaged what happens to the clutch disc, pressure plate and flywheel friction surface?

Answer 6

The clutch disc is held tightly between the pressure plate and flywheel friction surfaces

Question 7

What dictates a clutch as a PUSH or PULL type?

Answer 7

The direction the release bearing is moved to release the clutch

Question 8

Heavy duty vehicles use what type of clutch?

Answer 8

Pull type

Question 9

The release bearing pushes or pulls on what component within the clutch?

Answer 9

Release levers

Question 10

When the clutch disc is disengaged what moves together?

Answer 10

Clutch cover/pressure plate assembly rotates with the flywheel

Clutch discs rotates with the transmission input shaft

Question 11

When a clutch is getting ridden a lot what will wear?

a) flywheel
b) clutch disc
c) friction material
d) pressure plate

Answer 11

c) The clutch friction material - lining

Question 12

When a spring has to travel further what happens to its pressure application ability?

Answer 12

it gets weaker

Question 13

Does clutch pedal free play become more or less when the clutch is worn severely?

Answer 13

Less free play

Question 14

What are two things that dictate if the clutch is a push or pull type?

Answer 14

Release bearing travel and release levers travel

Question 15

What are the four ways to find the size of a clutch?

Answer 15

• Diameter of the disc
• Outside diameter of the clutch shaft
• Number of splines in the hub
• Number of dampening springs

Question 16

What are two types of flywheels?

Answer 16

Flat and Countersunk

Question 17

When an operator releases the pedal, what position is the clutch in?

Answer 17

Engaged

Question 18

What are the actuation mechanisms used for clutches?

Answer 18

• Mechanical linkage
• Hydraulic
• Air

Question 19

In a vehicle where the transmission/engine are VERY far from the operator pedal, what actuation mechanism is used?

Answer 19

Hydraulic
or
Air over Hydraulic

Question 20

If the engine/transmission is close to the operators clutch pedal, what actuation mechanism is most likely to be used?

Answer 20

Mechanical Linkage

Question 21

If a clutch pedal linked to a mechanical linkage has lots of free play but the clutch is adjusted correctly, what is cause?

Answer 21

The bearings, rod end and/or bushings in the linkage are worn

Question 22

Out of the three clutch actuation mechanisms, which is the least expensive?

Answer 22

Mechanical linkage

Question 23

If there are air bubbles in the hydraulic clutch system, what is the operators complaint?

Answer 23

Spongy pedal

Question 24

If a clutch pedal has excessive side to side movement, what should a tech be looking for as the cause?

Answer 24

Worn bushings in the pedal linkage

Question 25

What are basic inspections on a hydraulic clutch that a technician can do?

Answer 25

Check lines for damage and wear Check for leaks Pedal movement/feel Reservoir level and fluid condition

Question 26

When installing a new master cylinder in a hydraulic clutch assembly what should be done FIRST?

Answer 26

Bench bleed the master cylinder

Question 27

A rod end link is considered failed when what movement is felt?

Answer 27

The ball can move separately from the socket

Question 28

In an air over hydraulic clutch mechanism, which one is used for the control and which one is used as the assist?

Answer 28

Hydraulic - Control Air - Assist

Question 29

What drives the intermediate plate in a system with a countersunk flywheel system?

Answer 29

Flywheel

Question 30

What is the purpose of an intermediate plate?

Answer 30

Additional friction surface when using multiple friction discs

Question 31

Where are rigid clutches used? What type of application?

Answer 31

Where there is a limited amount of engagement and disengagement

Question 32

Are dampened clutch discs considered flexible or rigid?

Answer 32

Flexible

Question 33

What is used on a dampened clutch disc to absorb torsional shock loads?

Answer 33

A spring-loaded, limited-movement mechanism

Question 34

What do dampened clutch discs do to the service life of the clutch?

Answer 34

Extend clutch service life

Question 35

What are the two types of clutch disc linings materials?

Answer 35

Organic and Ceramic

Question 36

What clutch disc lining should be used where high heat will be encountered?

Answer 36

Ceramic

Question 37

An intermediate plate is used when?

Answer 37

Two clutch discs are used

Question 38

What component helps stop intermediate plate vibrations and reduce noise?

Answer 38

Anti-rattle springs

Question 39

How is the intermediate plate coupled to the clutch cover?

Answer 39

Drive Straps Drive Slots

Question 40

A clutch that sounds like it is "rattling" when engaged could be a result of?

Answer 40

A broken dampening springs in the clutch disc

Question 41

A clutch is starting to feel like its causing hard shifts, what could be the cause?

Answer 41

Broken dampening springs in the clutch disc

Question 42

How much gap should there be between the yoke and release bearing?

Answer 42

1/8"

Question 43

Operator complains the clutch is feeling stiff or harder, what could be the cause?

Answer 43

Worn clutch disc

Question 44

What generally causes premature failures of transmissions and clutches?

Answer 44

Abuse from operator

Question 45

What can cause a failure of a self-adjuster in the clutch?

Answer 45

Contamination - tiny teeth

Question 46

Which type of clutch can have an internal threaded ring that you must unlock first before adjusting the clutch?

Answer 46

Pull-type, manualy adjusted clutch

Question 47

When does a clutch brake activate?

Answer 47

When the clutch pedal is fully depressed. When the operator is shifting from neutral to first or reverse gear

Question 48

What does a clutch brake prevent?

Answer 48

Gear teeth clash during gear selection

Question 49

What is the purpose of the clutch brake?

Answer 49

To stop rotation of the transmission input shaft

Question 50

# True or False The release bearing pushes up against the clutch brake when the clutch is disengaged.

Answer 50

True

Question 51

At what point in clutch pedal travel should the clutch brake activate?

Answer 51

1/2"-1" from the floor (bottom of travel)

Question 52

What can cause premature failure of the clutch brake?

Answer 52

contamination, improper use

Question 53

Operator complains the truck is hard to get into 1st gear and reverse gear, what could be the cause?

Answer 53

Failed clutch brake

Question 54

What is considered improper use of the clutch brake?

Answer 54

Engaging the clutch brake while traveling in 2-6th gear

Question 55

If a clutch brake is able to slip, what will happen to service life of the component?

Answer 55

service life will be extended

Question 56

What will prolong clutch service life?

Answer 56

regular inspection, adjustment, keep clean

Question 57

Lubrication contamination of the clutch lining could give what symptom?

Answer 57

Chatteringing during engagement and disengagement

Question 58

A glazed clutch disc that is worn in an unusual pattern could be caused by?

Answer 58

Lubrication contamination

Question 59

What should be used when moving the heavy clutch assembly away from the engine?

Answer 59

Two Long Guide Studs

Question 60

What should be used to help control the clutch discs while the clutch is installed?

Answer 60

Clutch disc aligning tool

Question 61

What must be done before setting the clutch free pedal?

Answer 61

Check all of the external linkage for wear and signs of binding, must be properly lubricated

Question 62

To check the flywheel bore runout, what position does the dial-indicator need to be in?

Answer 62

90° to the surface

Question 63

Why should you check crankshaft end play more than once?

Answer 63

To squeeze out oil film, giving a more accurate reading

Question 64

What should never be used to clean clutch components?

Answer 64

Grease, oil based products, varsol

Question 65

An operator complains the clutch feels like it is dragging/grabbing. What could be the cause?

Answer 65

Flywheel face runout is beyond specs

Question 66

What two forces do centrifugal clutches utilize?

Answer 66

Centrifugal force Friction Force

Question 67

What could cause a centrifugal force clutch to stay engaged?

Answer 67

Release/return springs have failed

Question 68

Which component is spring controlled in a centrifugal force clutch?

Answer 68

Friction shoes

Question 69

In what applications would a rigid clutch disc be used?

Answer 69

Where limited amount of engagement and disengagement occur

Question 70

Push type clutches are usually used on what class of vehicle?

Answer 70

light-medium duty

Question 71

What causes the MOST wear to a clutch friction disc?

Answer 71

Clutch slippage

Question 72

The springs inside a clutch friction disc are called what?

Answer 72

Torsion Dampening springs

Question 73

What are the two design types of clutch covers?

Answer 73

Cast Iron: -Heavy duty use Stamped Steel: -High speed & light duty use ## Footnote 401A Pg. 12

Question 74

What are the advantages of cast iron clutch covers?

Answer 74

Handles high heat and high torque loads ## Footnote 401A Pg. 12

Question 75

What are advantages of the stamped steel clutch covers?

Answer 75

Lighter design and allow for higher engine speeds ## Footnote 401A Pg. 12