Flashcards in 401a Clutch Fundamentals and Service (On-Road) Deck (24):
Spring-loaded clutches may be push or pull-types. Explain the basic difference between the two designs.
Push-type clutches move the release bearing toward the engine during disengagement, while pull-type clutches move the release bearing toward the transmission during disengagement.
Identify three (3) methods used to activate a clutch.
- mechanical - rods, levers, pins, yokes and linkages.
- hydraulic - clutch master cylinder, connecting lines and hoses and a slave cylinder.
- air - clutch master cylinder, connecting lines and compressor.
Identify two (2) main types of flywheel designs used in mobile equipment.
- flat - friction surface and clutch cover mounting surface at the same height.
- countersunk - friction surface recessed below clutch cover mounting surface
Clutch covers are only constructed of cast iron.
false; Clutch covers can be constructed as a steel stamping.
Explain the function of a clutch cover.
Clutch covers are used to drive the pressure plate. They also contain the pressure springs used to apply force on the pressure plate. Clutch covers mount the pressure
plate assembly on the flywheel.
Identify three (3) main types of pressure springs used to apply force on the pressure plate.
- perpendicular coil springs.
- angled coil springs.
- diaphragm spring.
During the disengagement process, the clutch release levers move the clutch release bearing.
false; The clutch release bearing moves the clutch release levers.
Identify three (3) drive members in a dual disc clutch assembly.
- clutch cover/pressure plate assembly
- intermediate plate
Clutch discs may be of the dampened design. Explain why such a clutch disc would be used.
Different types of springs and clutch disc construction features provide various methods of absorbing torsional shock loads and other impact loads during engagement.
Explain why a clutch release bearing is used.
A rotating release bearing will minimize wear of the release levers during the engagement/disengagement process.
Clutch brakes are fully applied every time a gear selection is made.
false; Clutch brakes should only be used when shifting into first or reverse.
Identify two (2) possible ways an operator could cause a clutch problem.
- Riding (slipping) the clutch, by resting a foot on the pedal during vehicle operation.
- Shifting gears without using the clutch.
- Starting the vehicle in the wrong gear for the load conditions.
- Improperly using the clutch brake.
Explain the safety precautions required prior to removing a transmission from a vehicle.
Disconnect the battery ground cable to prevent engine operation. Use suitable lifting/lowering equipment. Keep out of the areas where you may get trapped if the lifting/lowering equipment fails or if the transmission swings out of control.
Flywheel, clutch housing and transmission housing face runout checks are conducted to ensure components will be parallel to one another during operation.
Crankshaft, flywheel and clutch housing bore checks are conducted to ensure the centrelines of the crankshaft and transmission input shaft are in line with one another.
Explain the function of flywheel guide studs, clutch cover/pressure plate assembly guide studs and clutch disc aligning shafts.
These support the weight of the various assemblies as they are removed, or being placed in position. They also help to accurately position the assemblies in relation to one another during the installation process. By supporting the component weight, they help protect associated parts from damage during removal and installation.
A specific loosening and torque pattern is used when removing and installing clutch-related components.
A normal clutch will lose clamping load when the lining material wears.
Auto wear compensation is as effective for push clutches as for pull clutches.
Adjustment for wear is made by the toothed slide.
An engine drive uses the spring controlled centrifugal clutch so as to allow for engine idling.
List the common connections between the drive units and driven units when a centrifugal clutch is used.
- close coupled
- flex couples
State the two (2) forces that react when the centrifugal clutch engages.
- centrifugal force
- friction force