Clutch Assembly
DESCRIPTION
Never use any type of petroleum-based fluid (engine oil, transmission oil, power steering fluid, etc.) in the clutch hydraulic system. Use of such fluids will result in master/slave cylinder seal damage, and cause a failure of the hydraulic clutch release system.
Brake fluid will damage painted surfaces. If brake fluid is spilled on any painted surfaces, wash it off immediately with water.
Do not contaminate the friction material with grease or oil since this may cause excessive slippage between the pressure plate and the clutch discs burning the friction material leading to an early failure of the clutch.
CLUTCH
The clutch assembly controls the transfer of torque from the engine flywheel to the manual transmission input shaft. The clutch assembly consists of the two discs, two plates and cover. The clutch disc consists of multiple friction material surfaces positioned on a metal frame and a free floating center hub. The clutch discs may have damping characteristics. The clutch cover assembly consists of 2 cast pressure plates and a heat treated steel spring contained under a stamped steel cover. It is bolted to the engine flywheel and exerts load against the clutch friction discs. The spring is segmented at the inside diameter. These segments (called fingers) are compressed by the clutch release bearing.
FLYWHEEL
The Dual Mass Flywheel is used on all engines. The flywheel incorporates the ring gear (5) around the outer circumference to mesh with the starter to permit engine cranking. The primary flywheel (6) side is bolted to the crankshaft. The secondary flywheel (3) side serves as the driving member to the clutch discs. Internal springs (4) between the flywheels are use to dampen energy. The Dual Mass Flywheel is serviced as an assembly only and should never be taken apart.
The flywheel is bolted firmly to the crankshaft which transmits part of the engine torque to the clutch discs. The rest of the torque passes into the cover through the bolts holding the clutch to the flywheel. From there, the straps transfer it to the clutch pressure plates. The diaphragm spring clamps the pressure plates against the clutch discs to achieve positive lock-up with flywheel. The clutch discs transmits the entire engine torque to the transmission via splined connection to the transmission input shaft. When the driver depresses the clutch pedal, the release bearing actuate the diaphragm spring pivots on this fulcrum ring, so that the outside diameter moves away from the pressure plate. This causes the pre-loaded drive straps to pull the pressure plates away from the clutch discs, interrupting torque transmission. When the driver releases the pedal, the outer portion of the diaphragm springs act on both of the pressure plates which clamp both discs with the dual mass flywheel.
CLUTCH HYDRAULIC SYSTEM
The hydraulic clutch system uses brake fluid stored in the brake master cylinder reservoir (1). The clutch supply hose (2) picks up the fluid at a point above the minimum brake fluid level and provides fluid to the clutch master cylinder (4). Because the reservoir contains a protected volume for the clutch, the hydraulic brake system will not lose fluid in the event of a fluid leak in the hydraulic clutch system. The clutch master cylinder (4) is twisted into the dash panel. The input rod of the clutch master cylinder goes through the dash and is snapped onto a pin on the clutch pedal (3). The clutch slave cylinder (6) is mounted outside the bellhousing and has an output rod that sits in the cup of the clutch release fork. It is connected to the clutch master cylinder by a clutch line (5). This allows the brake system to maintain an adequate volume of fluid to operate in the event of a fluid leak in the hydraulic clutch system.
OPERATION
FLYWHEEL
The flywheel serves to dampen the engine firing pulses. The heavy weight of the flywheel relative to the rotating mass of the engine components serves to stabilize the flow of power to the remainder of the drivetrain. The crankshaft has the tendency to attempt to speed up and slowdown in response to the cylinder firing pulses. The flywheel dampens these impulses by absorbing energy when the crankshaft speeds and releasing the energy back into the system when the crankshaft slows down.
CLUTCH OPERATION
The flywheel is bolted firmly to the crankshaft which transmits part of the engine torque to the clutch discs. The rest of the torque passes into the cover through the bolts holding the clutch to the flywheel. From there, the straps transfer it to the clutch pressure plates. The diaphragm spring clamps the pressure plates against the clutch discs to achieve positive lock-up with flywheel. The clutch discs transmits the entire engine torque to the transmission via splined connection to the transmission input shaft. When the driver depresses the clutch pedal, the release bearing actuates the diaphragm spring pivots on this fulcrum ring, so that the outside diameter moves away from the pressure plates. This causes the pre-loaded drive straps to pull the pressure plates away from the clutch discs, interrupting torque transmission. When the driver releases the pedal, the outer portion of the diaphragm springs acts on the pressure plates which in turn clamps the clutch discs between the pressure plates and the flywheel.