GM Service Manual Online
For 1990-2009 cars only

Hydraulic Clutch Section View


Object Number: 460826  Size: MH
(1)Crank Shaft
(2)Flywheel
(3)Clutch Disc
(4)Pressure Plate
(5)Clutch Cover
(6)Diaphragm Spring
(7)Release Bearing
(8)Input Shaft Bearing
(9)Input Shaft
(10)Operating Cylinder
(11)Clutch Housing
(12)Release Fork

The clutch is a diaphram-spring clutch of a dry single disc type. The diaphram spring (6) is of a tapering-finger type, which is a solid ring in the outer diameter part, with a series of tapered fingers pointing inward. The disc, carrying torsional coil springs, is positioned on the transmission input shaft with an involute spline fit.

The clutch cover is secured to the flywheel, and carries the diaphram spring in such a way that the peripheral edge part of the spring pushes on the pressure plate (4) against the flywheel with the disc in between, when the clutch release bearing (7) is held back. This is the engaged condition of the clutch.

With the clutch pedal depressed, the clutch master cylinder becomes pressurized from the force of the push rod into the master cylinder. This forces hydraulic fluid into the hydraulic line to the actuator cylinder. The actuator cylinder then pushes the release fork (12) to engage the release bearing to advance and push on the tips of the tapered fingers of the diaphram spring. When this happens, the diaphram spring pulls the pressure plate away from the flywheel, thereby interrupting the flow of drive from the flywheel through the clutch disc to transmission input shaft.