Clutches
What
is a clutch?
There are a number of mechanisms involved in converting the turning
motion produced by a car's engine to the turning motion of the wheels.
These are the clutch, gearbox, propeller shaft and final drive.
These
4 items together are called the "transmission". Whenever the engine is
running the crankshaft is turning . The clutch is the connection
between the rotating crankshaft and the gearbox.
When
the clutch pedal is in the normal "up" position (engaged) the plates in
the clutch press together and transfer the turning motion to the
gearbox. In "neutral" no gear is selected so this motion is not passed
on to the road wheels and the car stays still. When a gear is selected
the gear wheels engage and the motion is passed on to the wheels.
When
the clutch pedal is pushed "down" (disengaged), the plates in the
clutch are pulled apart a little and the turning motion is not passed
on to the gearbox.
Below are the common symptoms that you could experience when having trouble with your clutches.
Judder
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
Slip
SYMPTOMS
Engine accelerates without giving a correspondence increase in vehicle speed
Burning smell
Vehicle will not drive up steep hills
CAUSE
Incorrect clutch adjustments
Partial seizure of linkage or fouling of pedal preventing the full return of the linkage
Worn clutch facings
Oil contaminated facings
Defective pressure plate and/or broken springs
Partially seized mechanism
Drag
SYMPTOMS
Difficulty in engaging first gear from neutral without making noise
Jolt when changing gear with the vehicle in motion
Vehicle moves when pedal is fully depressed
CAUSE
Incorrect clutch adjustments or lack of fluid in the hydraulic operating system
Worn hydraulic system
Oil contaminated facings
Defective driven plate, buckled plate or seizure on spines
Seized spigot bearing or worn spigot
Fierceness
SYMPTOMS
A sudden move off of the vehicle though the pedal is 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