Chapter 3 Clutches

When discussing common causes of problems with clutch systems with adjustable linkage, Technician A says that often problems can be corrected by properly adjusting the clutch linkage. Technician B says that excessive clutch pedal free travel can indicate an excessively worn clutch disc. Who is correct?

A only

When discussing pilot bearings or bushings, Technician A says that they are often eliminated in front-wheel drive vehicles. Technician B says that they serve as a low-friction pivot point for the clutch linkage. Who is correct?

A only

When reviewing the procedure for adjusting a clutch pedal, Technician A says that 1 inch of pedal free travel is normal on most vehicles. Technician B says that the clutch master cylinder pushrod should be adjusted for constant light pressure on the piston. Who is correct?

A only

While discussing semi-centrifugal pressure plates, Technician A says they alter the holding force of the clutch assembly in response to engine speed. Technician B says they require high pedal effort at low engine speeds. Who is correct?

A only

A clutch housing is also called a

Bell housing

When discussing release bearings, Technician A says that constant running release bearings are used with hydraulically controlled clutches. Technician B says that the release bearing moves the pressure plate fingers to disengage the clutch. Who is correct?

Both A and B

When discussing self-adjusting clutch cables, Technician A says that a toothed wheel and a pawl are used to adjust the cable for clutch disc wear. Technician B says that the self-adjusting unit maintains the desired amount of free-play. Who is correct?

Both A and B

When discussing the operation of the clutch assembly, Technician A says that when the pedal is depressed, the release bearing is pushed against the release fingers of the pressure plate, which releases the plate's pressure on the clutch disc. Technician B says that the clutch disc is pressed against the flywheel by the pressure plate. Who is correct?

Both A and B

When discussing the purpose of the flywheel, Tech a says that it serves as a heat sink for the clutch disc, Tech b says that it serves as a vibration dampener for the engine.

Both tech A and B

When discussing the dual-clutch systems, Technician A says that all dual-clutch systems use wet clutches. Technician B says that dual-clutch systems require the use of a clutch pedal. Who is correct?

Neither A nor B

When discussing the major components of a hydraulic clutch linkage, Technician A says that the master cylinder for the car's brakes is also used for the clutch. Technician B says that the slave cylinder is directly connected to the clutch pedal and increases hydraulic pressure as the pedal is depressed. Who is correct?

Neither A nor B

While discussing hydraulic clutch systems, Technician A says the slave cylinder responds directly to the clutch pedal and sends hydraulic fluid to the clutch master cylinder. Technician B says the clutch delay valve between the master and slave cylinder allows for immediate clutch release. Who is correct?

Neither A nor B

pilot bearing

Supports the transmission input shaft where it mates with the crankshaft

When discussing where a clutch disc is normally mounted; Tech A says that it is bolted to the flywheel, Tech b says that it is splined to the transmission input shaft.

Tech B only

When discussing clutch problems, Technician A says that a stretched clutch cable could cause gear clash when shifting. Technician B says that a leaking slave cylinder could cause premature release bearing wear. Who is correct?

Tech a

Which of the following statements about the torsional springs in a clutch disc is not true? A. They dampen vibrations coming from the transmission and drive shaft. B. They may be tuned to a particular engine and driveline. C. They cushion the sudden load on the disc when it is quickly engaged. D. They are only found on flexible clutch dics.

They dampen vibrations coming from the transmission and drive shaft

flywheel noises

a loose flywheel will cause a knocking sound similar to an engine bearing knock.

When discussing ways to determine if a pilot bushing bearing is faulty, Technician A says that a faulty pilot bearing will squeal constantly when the engine is running. Technician B says that a careful inspection of the transmission input shaft can determine the condition of the pilot bushing bearing. Who is correct?

b only

flywheel

balancer for engine, adds inertia to the rotating crankshaft, provides surface for clutch, flexplates replace flywheels in automatic trans

clutch chatter causes

bent clutch disc burned or damaged disc facing excessive heat (caused by driving riding clutch) damaged pressure plate

A clutch replacement has just been performed on a vehicle. The transmission shifts perfectly when the engine is turned off. However, when the engine is started, severe gear clashing occurs whenever shifting into reverse gear is attempted. Shifting into the forward ranges is very difficult. Technician A says that there may be excessive clutch pedal free-play. Technician B says that there may be air in the clutch hydraulic system. Who is correct?

both a and b

When discussing the causes of rapid clutch disc wear, Technician A says that driving habits influence how long a clutch assembly will last. Technician B says that insufficient pedal free travel will cause the disc to wear rapidly. Who is correct?

both a and b

When discussing the operation of a vehicle with a dual-mass flywheel, Technician A says that the flywheel should be checked for excessive rotation between the primary and secondary plates. Technician B says that replacing the dual-mass flywheel with a single-mass unit might result in neutral-rollover gear rattle. Who is correct?

both a and b

When discussing the possible causes for damage to the surface of a pressure plate, Technician A says that a worn clutch disc can score the surface. Technician B says that insufficient pedal free travel or riding the clutch can cause it to overheat. Who is correct?

both a and b

When installing a pressure plate, Technician A says that pressure plate bolts are tightened one at a time in a circular pattern. Technician B says that the dowel pins locate the pressure plate to ensure that proper balance of the clutch assembly is maintained. Who is correct?

both a and b

The pressure plate engages and disengages the

clutch disc

Clutch housing

connects engine and transmission, houses clutch assembly

hydraulic clutch linkage

consists of a master cylinder, hydraulic tubing, and a slave cylinder, and a concentric slave cylinder

The pressure plate moves away from the flywheel when the clutch pedal is

depressed

clutch problems (slippage)

evident when the driver has the clutch engaged and the engines speed increases but the vehicles road speed does not. Most obvious during acceleration and shifting. Caused by - oil soaked or worn disc facing, warped flywheel or pressure plate, weak pressure plate springs, release bearing contacting the fingers of the pressure plate.

The clutch disc slides over the splines of the _______ shaft

input

causes of noise while shifting

low fluid in hydraulic system air in the hydraulic system clutch linkage out of adjustment worn or damaged internal shift mechanicms worn or damaged sliding gears and/or synchronizers misaligned TRANS HOUSING worn or damaged shafts

hydraulic clutch diagnosis

make sure fluid is at proper level check master and slave cylinder for leaks bleed system whenever it is opened for service some systems require periodic adjustments

A hydraulic clutch consists of a (an) _____ , a (an) _______ , and a (an) _______.

master cylinder / hydraulic tubing / slave cylinder

noises and vibrations

mostly caused by bearings and bushings. release bearings make a whirring, grating, or grinding noise. (occurs when clutch pedal is depressed and stops when the pedal is fully released.) Pilot bearing noises sound like a squeal or howl (most noticeable in cold weather.)

When reviewing the procedure for installing a clutch disc, Technician A says that the disc should always be installed with its hub and springs toward the engine. Technician B says that the splines of the disc should be clean, dry, and never oiled or greased. Who is correct?

neither a nor b

clutch problems (drag)

occurs when the clutch disc is not fully released when the clutch pedal is fully depressed, most noticeable shifting into reverse, can because by air in a hydraulic system, a loose disc facing, incorrect clutch pedal adjustment, a defective release lever, a warped pressure plate or disc.

RELEASE BEARING (THROW OUT BEARING)

operated by clutch linkage, presses against the pressure plate to release the clutch, transmits movement of the clutch linkage to the pressure plate.

clutch operation

pressure plate engages clutch by pressing the disc against the flywheel > pressure plate moves away from the flywheel when clutch is depressed > clutch release bearing is operated by the clutch linkage > when clutch is depressed, bearing moves toward the flywheel

There are two types of dry clutch discs:

rigid and flexible

Tension is maintained in a self-adjusting cable-type clutch linkage by the use of ________ and a toothed _______

spring / wheel

pressure plate assembly

squeezes clutch disc onto flywheel

The teeth around the outside of the flywheel form a ring gear for the

starting motor

clutch disc

steel plate covered with frictional material, squeezed between the flywheel and pressure plate, transmits power from engine crank to trans input shaft

A brief squeal comes from the clutch/transmission area of a vehicle just as the clutch is being engaged. There is no noise when the clutch is fully engaged. Technician A says that the clutch pilot bearing may be worn out. Technician B says that the transmission input shaft bearing may be faulty. Who is correct?

tech a

A bearing-type noise is heard immediately when the clutch pedal is depressed. As the pedal is pushed to the floor, the noise remains about the same. When the clutch pedal is released, the noise disappears. Technician A says that the clutch pilot transmission input bearing could be at fault. Technician B says that the clutch release bearing could be at fault.

tech b

A customer says that occasionally when he is at a stoplight with the transmission in first gear and the clutch pedal depressed the vehicle will begin to move by itself. Technician A says that there may be insufficient clutch pedal free-play. Technician B says that the clutch master cylinder may be leaking internally. Who is correct?

tech b

electromechanical clutch systems

the clutch is actuated with an electronically controlled solenoid, rate of clutch release can be controlled by placing system in different driving modes.

clutch chatter

this normally occurs when the pressure plate first makes contact with the clutch disc and will stop when the clutch is fully engaged.

when the clutch is disengaged, the pressure plate is released by a

throw-out bearing

A flexible clutch disc has ______ springs in its center hub

torsional

clutch linkage

transfers the clutch pedal movement to the release bearing

self shifting manual trans

uses dual clutch arrangement (dry clutches - primarily used in vehicles with low engine torque/ wet clutches - used on more powerful engines, have multiples plates immersed in fluid.) Have two separate gear shafts, each with its own corresponding clutch.

mechanical clutch linkage

uses shafts, levers, and a bell crank or a cable