It is important to get specialist advice before fitting a new clutch as many symptoms could indicate a problem with the clutch, whilst the real fault may be something completely different such as engine revving, slipping fan belt or minor adjustment.
Common clutch faults are:
Symptoms: Severe low frequency vibration
Cause: Loose or worn engine mountings, misalignment of engine to gearbox, uneven operation of clutch arm, oil contaminated facings, defective pressure plate, defective driven plate, scored or glazed flywheel, worn spigot bearing
Symptoms: Engine accelerates without giving a corresponding increase in vehicle speed, burning smell, vehicle will not drive up steep hills.
Cause: caused by oil on the friction plate or worn friction plate.
Symptoms: The system of this would be difficulty in obtaining gear, particularly first and reverse gears and vehicle moves when pedal is fully depressed.
Cause: clutch cable not at correct adjustment or centre plate sticking on splines. Loss of pedal due to clutch fluid leak.
Symptoms: A sudden move of the vehicle though the pedal is being gradually released.
Cause: Partial seizure of linkage or fouling of pedal preventing the full return of the linkage, uneven operation of the clutch arm, worn hydraulic system, oil contaminated driven plate, misalignment of engine to gearbox, worn spigot bearing.
On modern vehicles it is becoming increasingly common that when a clutch is replaced the concentric slave cylinder (CSC) also requires replacement.
The assembly of a concentric slave cylinder is structured to allow it to operate directly in front of the clutch cover.
This new technology allows direct hydraulic load to be applied to the clutch via the master cylinder and concentric slave cylinder. As a result providing less pedal pressure, eliminating the potential loss of bearing travel caused by wear commonly associated in traditional linkage or cable type systems.
Advantages of Concentric Slave Cylinders:
• Self-adjusting system prolonging the life of your clutch
• Less moving parts which means there are less items to wear or fail.
The flywheel is a metal disc which is fitted directly onto the crankshaft between the engine and the clutch. Its purpose is to help provide a smooth transfer of power from the engine to the drive train. In essence, the flywheel gives your vehicle enhanced momentum and a smoother driving experience.
Indications of a worn flywheel are:
• Visible Grooves
• Visible glazing and/or cracks
Whenever a clutch is renewed, your flywheel should be inspected and, where necessary, skimmed or replaced.
Dual Mass Flywheel
Most new vehicles now come fitted with dual mass flywheels. These are essential components that allow an enhanced performance in the vehicles drivability. Additionally, these new components reduce harmful vibration.
A worn dual mass flywheel will affect the performance and efficiency of the new clutch and almost certainly result in premature failure.
Indications of a worn Dual Mass Flywheel are:
• Irregular noises
• Intermittent clutch slip