There are 3 different clutch assemblies used on this vehicle, depending on the engine application and the transmission. In order to perform the proper diagnosis and the correct repairs, it is important to understand which clutch assembly is being used and how it operates. The following components make up the clutch system:

Clutch Actuator Cylinder: The clutch actuator cylinder is a hydraulic cylinder mounted on the transmission. It moves the clutch lever by pressurized fluid against the piston.

Clutch Brake: The clutch brake is a disc with friction material that is tabbed to the input shaft. It is squeezed between the release bearing and the transmission front cover during clutch disengagement, to stop the rotation of the input shaft. The clutch brake is used with non-synchronized transmissions to allow shifting into a gear while the vehicle is not moving.

Clutch Cover: The clutch cover is part of the pressure plate cover assembly. It retains the springs and other levers that operate the pressure plate. The cover is bolted to the flywheel.

Clutch Disc: The clutch disc is referred to as the driven member. It is a flat plate that may have dampener springs. Depending on the clutch assembly, it may have either 4 or 6 paddles. The friction material located on the paddles is clamped between the flywheel and the pressure plate. The disc hub is splined on the input shaft and delivers the engine torque to the transmission. Different friction materials are used to give smooth and long lasting clutch operation. For increased engine torque applications 2 discs are sometimes used.

Clutch Hydraulic Pipes: The clutch hydraulic pipes are high-pressure hoses, or steel pipes, that deliver the fluid to the clutch actuator and returns the fluid to the master cylinder. The hydraulic pipes/hoses use quick connect fittings.

Clutch Lever: The clutch lever connects the clutch actuator cylinder to the clutch cross shaft.

Clutch Master Cylinder: The clutch master cylinder is mounted in the cab. It pressurizes the fluid by a piston, which is operated by the clutch pedal movement.

Clutch Pedal: The clutch pedal is mounted in the cab on a bracket. It is operated by foot pressure, swivels on a shaft, and assisted to the upright position by a spring.

Clutch Pressure Plate: The clutch pressure plate is referred to as the driving member. It is a steel disc with a machined surface that is forced against the clutch discs by the springs in the clutch cover.

Clutch Pressure Plate Cover Assembly: The clutch pressure plate cover assembly consists of the pressure plate, the cover, and the springs that apply the clamping force to the clutch discs.

Clutch Release Bearing : The clutch release bearing is attached to the clutch pressure plate. It moves the springs in the pressure plate to release the clamping load. The bearing may require routine lubrication or may be a sealed style.

Clutch Release Yoke: The clutch release yoke rotates with the cross shaft. It has fingers that move the clutch release bearing.

Cross Shaft: The cross shaft is a 2 piece shaft that goes through the clutch housing and is supported by bushings. The clutch release yoke fastens to the cross shaft.

Pull Type Clutch: With the pull type clutch, the release bearing is pulled away from the pressure plate cover assembly during clutch disengagement.

Push Type Clutch: With the push type clutch, the release bearing is pushed towards the pressure plate cover assembly during clutch disengagement.

The cab forward, or T model medium duty vehicle, uses a hydraulic assisted clutch system. The clutch master cylinder pressurizes the fluid in order to move the piston in the clutch actuator cylinder. The clutch actuator cylinder connects to the clutch lever and applies the force to move the release bearing.

Since the clutch is hydraulic operated, there is no free travel in the clutch pedal. When the clutch is engaged, the fingers on the release yoke rest against the release bearing. The clutch pedal height is determined by stopping against the clutch switch. Full movement of the pedal is required to move ample pressurized fluid to the clutch actuator cylinder. Without ample pressurized fluid, the clutch actuator cylinder will not move the release bearing to give full clutch disengagement, causing clutch drag, or the release bearing will not squeeze the clutch brake against the transmission, causing gear clashing.

Proper placement, or adjustment of the release bearing, is critical for correct pull type clutch operation. If the release bearing is too close to the pressure plate cover assembly, it may prevent complete clutch engagement. If the release bearing is too far from the pressure plate cover assembly, it may prevent complete clutch disengagement.

RPO MPM

The clutch assembly manufactured by Valeo can be used with any of the engine or transmission applications. The clutch is a 355.6 mm (14 in) with a single cerametallic disc, 6 paddles. The clutch operation is a diaphragm spring pull type. The clutch may be used with a clutch brake. The clutch is a self-adjusting clutch that should not require any adjustment.

RPO MPL

The clutch assembly is manufactured by Eaton Fuller. It can be used with any of the engine or transmission applications. The clutch is a 355.6 mm (14 in) with a single cerametalix disc. The clutch operation is pull type. It is self-adjusting and referred to as the Eaton Solo®. Sliding cams in the pressure plate cover assembly move the pressure plate as the clutch discs wear. The clutch also can be a maintenance free version. The clutch may be used with a clutch brake.

RPO MPK

The clutch assembly is manufactured by Eaton Fuller. It is used with any of the engine or transmission applications. The clutch is a 355.6 mm (14 in) with 2 ceramic discs. The clutch operation is pull type. It is self-adjusting and referred to as the Eaton Solo®. Sliding cams in the pressure plate cover assembly move the pressure plate as the clutch discs wear. The clutch also can be a maintenance free version. The clutch may be used with a clutch brake.