Hmmm...Where to begin?
The "clutch" is really two assemblies - A pressure plate that bolts to the FLYWHEEL of the engine, and the Clutch Pack - that rolls along in the splines that go to the TRANSMISSION.
How it's put together - the Clutch pack uses the Throw-out bearing which is mounted to the transmission housing thru the use of a fulcrum - a lever so to speak - that the Clutch pedal often called "Master" pushes fluid into a cylinder the "Slave" - at the Transmission housing where all this is housed. This slave then moves a lever or piston in the throw-out bearing making it apply pressure against a set of fingers. The bearing presses against the fingers of the pressure plate which then transfer this motion (fulcrum) to the clutch pack and the pads then get pushed away internally from the pressure plate itself.
Please understand that the Pressure Plate - is MOUNTED to the Engines Flywheel, and the Clutch pack, sits inside the pressure plate and rotates with the transmission. The Throw-out bearing rests on the fingers of the pressure plate and has a hole that allows the transmission side to rotate with the Clutch Pack. So, when the throw-out bearing presses on the fingers - the pack gets pushed away - the springs in the pack then force the pads back onto the pressure plate when the throw-out bearing pressure is released - Clutch pedal out.
This action lets the engine turn while the transmission can then be released or freed up to select another gear or place the transmission in a freewheeling state of Neutral (ride the clutch moments) .
So, these two parts - are how the Engine can transfer power to the Transmission - these two pieces are attached to two different shafts. allowing one to rotate and the other also to rotate or even become stationary (transmission side) using a third part as a lever or fulcrum to push against spring tension - and the springs help hold the clutch pack onto the pressure plate.
The 3rd piece is what brought you here...
What connects the two to make the system work, is the
THROWOUT BEARING which uses the Brakes Reservoir to hold fluid so the Clutch's "Master and Slave" of two pistons and a tube - can make or force the Throw-out bearing - to put pressure in the tiny fingers the Pressure plate has, and transfers that motion to the hub of the Clutch pack - that has a set of literally "brake" pads on a spring hinge that when the throw-out bearing presses against the fingers of the pressure plate - makes the Clutch pack and it's springs - bow-out inside a floating free spinning space of air between the pressure plate and flywheel - pushing out and removing the "pads" from the Pressure plate.- letting the two halves of the system to rotate at their own speed - letting you shift the transmission or allow the engine to apply power in a variable fashion to the transmission.
Since the Clutch Pack uses a fibrous softer material - the clutch pack can work as a means to apply friction across the pressure plate surface in a flexible force driven way - using the throw-out bearing - to act as a means to pull the pack away from the plate, and also let it meet with the plate but apply force for friction gradually - letting one turn faster than the other and yet apply power.
The Throw-out bearing may be the culprit, requiring a repair, or the Master/Slave unit is not allowing the engaging and disengaging of the Throw-out bearing to work correctly. Thats why I mentioned bleeding the system - unless you really ride the clutch - the vehicles mileage usually dictates when the system needs repair or replacement - usually above 50K miles or more and older than 5 years - then you need to worry.
The springs in the system - by default - are engaging the pressure plate which means the clutch pack and plate are one. When the system begins to slip - this usually means the clutch pack pads are worn down and cannot apply enough force as friction to keep the housing rotating as one - as the entire system - needs to be replaced as one unit.
If you're a mechanic, then I apologize for the redundancy - but I feel it is necessary to post this so others can grasp the way a clutch works so they can extend the life and enjoyment of manual transmissions with a better understanding.