There are 4 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 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 cable: The clutch cable transfers the clutch pedal motions to the clutch lever. The cable has adjustable ends for positioning the release yoke or fork.

Clutch lever:  The clutch lever connects the clutch cable to the clutch cross shaft.

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

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

Clutch fork: The clutch fork is connected to the clutch lever. It pivots on a ball stud in the clutch housing, and is used with push type clutches to move the release bearing.

Clutch release bearing : The clutch release bearing is attached to the clutch pressure plate on pull type clutches. On push type clutches, the release bearing slides on the tube of the input shaft bearing retainer. The release bearing moves the springs in the pressure plate cover assembly to release the clamping load. The bearing may require routine lubrication or may be a sealed style.

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 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 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 clutch 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 damper 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, two discs are sometimes used.

Clutch pedal free travel: The clutch pedal free travel is the amount the pedal moves before the clutch release bearing moves.

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 bus chassis vehicle uses a clutch cable to operate the clutch system. Movement from the clutch pedal is transmitted to the clutch lever and linkage through the clutch cable. Different configurations of linkage rotate the clutch release yoke or clutch fork, depending if the clutch assembly is a pull type or a push type.

Proper placement or adjustment of the release bearing is critical for correct pull type clutch operation. If the release bearing is too far from the pressure plate cover assembly, it may prevent complete clutch disengagement. On the RPO MPJ, improper clutch pedal free travel may cause release bearing failure.

RPO MPJ

The clutch assembly manufactured by Valeo is used with the 8.1 L engine. The clutch is a 330.2 mm (13 in) push type. A clutch fork that pivots on a ball stud in the clutch housing is used to move the release bearing. Adjusting the clutch linkage moves the clutch fork for the proper clutch free travel.

RPO MTD

The clutch assembly manufactured by Valeo is used with the Caterpillar engines. The clutch is a 355.6 mm (14 in) with a single cerametallic disc. The clutch operation is a diaphragm spring pull type. The clutch release bearing travel is adjusted by loosening the lock ring on the collar and turning the coupler.

RPO MWM

The clutch assembly manufactured by Eaton Fuller is used with the Caterpillar engines. The clutch is a 355.6 mm (14 in) with a single cerametalix disc. The clutch operation is a stamped angle spring pull type. The clutch release bearing travel is adjusted by manually turning the pressure plate inside of the clutch cover. A Kwik-Adjustâ® aids the clutch adjustment. The release bearing requires routine greasing.

RPO MZE

The clutch assembly manufactured by Eaton Fuller is used with the Caterpillar engines. The clutch is a 355.6 mm (14 in) with 2 cerametalix disc. The clutch operation is a stamped angle spring pull type. The clutch release bearing travel is adjusted by manually turning the pressure plate inside of the clutch cover. A Kwik-Adjustâ® aids the clutch adjustment. The release bearing requires routine greasing.