Hummer H3. Manual — part 926

Fig. 29: Clutch Pedal
Courtesy of GENERAL MOTORS CORP.

The clutch pedal, mounted on the engine cowl, is designed to compress the clutch hydraulic fluid
with little driver effort. The pedal swivels on bushings. The clutch master cylinder pushrod
connects to a pin on the pedal. A spring, located inside of the clutch master cylinder, returns the

2007 Hummer H3

2007 TRANSMISSION Clutch - H3

pedal to the correct position after depressing.

Fig. 30: 5 Speed Transmission Hydraulic Clutch System
Courtesy of GENERAL MOTORS CORP.

The reservoir, which is part of the master cylinder, supplies the fluid at the front of the master
cylinder through the center feed port (1). The center feed port allows the flow of fluid from the
reservoir to the cylinder when the pedal is in the complete returned position. The master cylinder
uses a spring (3) to return the piston (2) to the clutch engagement position. When the clutch pedal
is depressed, the piston moves forward in the cylinder, compressing the fluid. The compressed
fluid travels through a hose to the clutch actuator cylinder. A bleeder screw (4) is located at the
clutch actuator cylinder for bleeding the hydraulic system.

2007 Hummer H3

2007 TRANSMISSION Clutch - H3

Fig. 31: View Of Clutch Actuator Cylinder & Release Bearing
Courtesy of GENERAL MOTORS CORP.

The clutch control actuator cylinder disengages the clutch, using the pressurized fluid from the
clutch master cylinder. The clutch control actuator cylinder is fastened to the front of the
transmission. The clutch release bearing is attached to the control actuator cylinder. The control
actuator cylinder has a piston, which has seals that slide on the housing assembly. There is a
spring between the piston and the housing to keep the piston at the extended position, allowing
the release bearing to be in constant contact with the pressure plate fingers. The movement of the
piston, by the pressurized fluid, pushes the release bearing against the tips of the clutch pressure
plate fingers, to disengage the clutch.

As the clutch wears, the piston or release bearing, moves toward the transmission. The piston is at
the furthest position from the transmission with a new clutch.

The clutch control actuator cylinder has a bleeder, for bleeding the air out of the hydraulic
system.

2007 Hummer H3

2007 TRANSMISSION Clutch - H3

Ball bearings enable the release bearing to turn, while applying pressure to the pressure plate
fingers. Using an angular contract style bearing allows the release bearing to be in constant
contact with the pressure plate fingers.

Fig. 32: View Of Pressure Plate Assembly
Courtesy of GENERAL MOTORS CORP.

The diaphragm spring clutch consists of a pressure plate (2), a diaphragm spring (3), a pivot ring
(4), drive straps (5) and a cover (1). When the release bearing contacts the tips of the diaphragm
spring fingers, it moves them toward the flywheel. The outside diameter of the diaphragm spring
pivots on a pivot ring inside the cover. This action lifts the pressure plate off the flywheel through
the drive straps, which connect the cover to the pressure plate. As the clutch wears, there is an
increase in pedal effort.

2007 Hummer H3

2007 TRANSMISSION Clutch - H3