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In an Automobile, What is a Pressure Plate?

Long style pressure plates are mainly used for drag racing.
A car clutch, which is connected to the pressure plate.
Friction makes brake drums and pads work together.
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  • Written By: Eric Tallberg
  • Edited By: O. Wallace
  • Images By: John Heard, n/a, Tarasov_Vl
  • Last Modified Date: 22 August 2014
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The pressure plate is an integral factor in the function of an automobile’s manual transmission. It pushes the clutch disc, sometimes called the clutch plate, against the constantly spinning engine flywheel. The clutch disc is either stationary or rotating, and friction material, similar to that found on brake pads and brake drums, causes the disc to spin at the same speed as the engine flywheel. It is this friction between the clutch disc and flywheel that allows the engine torque to drive the wheels.

Pressure plates are, as the name implies, round, metallic devices containing springs and fingers, or levers, and controlled by the release fork connected to the shifter. All of the clutch components are enclosed in the bell housing of the transmission, between the rear of the engine and the front of the gearbox.

When the driver steps on the clutch pedal, a number of springs in the pressure plate are compressed by multiple — most often three — fingers. This compression of the spring(s) pulls the plate and the clutch disc away from the flywheel and prevents the clutch disc from rotating. When the clutch disc is stationary, the driver can shift into the proper gear and release the clutch pedal. When the pedal is let up, the fingers release their grip and the spring(s) expand to push the plate into the clutch disc, thereby engaging the flywheel. This release process is often called the “clamp load.”

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There are three major types of pressure plates:

  1. The Long style contains nine coil springs for pressure against the flywheel and three thin fingers for release. It is used mainly for drag racing.

  2. The Borg & Beck style also contains nine coil springs and three fingers. The fingers are wider, however, and the plate has the more robust materials and design necessary for street driving.

  3. The diaphragm pressure plate is best suited for street use and is, therefore, the most common type found on later-model automobiles. It contains a single Bellville-style spring that applies a more even load from clutch plate to flywheel. Because the single-spring diaphragm is more effective “over-center”, there is also less effort needed by the driver to hold the clutch pedal in the depressed position at a stop.

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Discuss this Article

anon957857
Post 10

Why adjusting bolts given in the pressure plate?

anon278371
Post 9

I have replaced a clutch plate and drove my srx (Hilux) 2y Engine for only two weeks. Now I cannot drive it; the gears are engaging with or without the clutch pedal even if the engine is running. What can be the problem with my hilux?

anon41981
Post 4

what causes the pressure plate to wear if the clutch is good?

anon38021
Post 3

sir what is clutch plate and its function? I need basic carification.

anon35865
Post 2

what causes a clutch pressure plate to warp?

anon32247
Post 1

What materials are generally used for the clutch pressure plate?

How to increase the wear resistance of the Pressure Plate in a dry clutch assembly used in commercial vehicles?

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