Pressure Plates
All manual transmissions need a clutch system in order to shift gears. Most of the cars and trucks on the streets today have a manual transmission will have a pressure plate in the clutch assembly. The pressure plate is necessary component in the clutch system on vehicles. There are three kinds of pressure plates. A pressure plate bolts on the clutch disk when you push the clutch pedal in and is attached to the engine flywheel. When pressure from the clutch pedal is applied it will engage tension on the springs which force the pressure plate against the flywheel and allow for the transfer of power from the engine to the gearbox.
The three kinds of pressure plates that are used today are the Borg & Beck, the Long style and the diaphragm type pressure plates. The first two are generally used for street racing applications, while the third type is used for everyday driving applications.
Borg & Beck Pressure Plate
The Borg & Beck type pressure plate is good for use in everyday driving, but it can be used in certain applications that require high rpms and when high horsepower applications are needed. In these types of racing applications, the Borg & Beck type offers centrifugal assist. The Borg & Beck type has three wide fingers on it coil springs under the pressure plate “hat”. The pressure plate is released when the coil springs are compressed.
Long Style Pressure Plate
The Long style pressure plate has three thin fingers on it instead of three wide fingers like the previous type. These three fingers are there to engage the release bearing. What makes this type unique is that it also has nine coil springs. The clutch is released when you compress the springs by stepping on the clutch pedal. Centrifugal loading can be increased with this type if small weights are added which is useful for certain driving situations. In fact, this type is the most popular type to use for drag racing applications. Most race cars have the Long style pressure plate in the clutch assembly.
Diaphragm Pressure Plate
The best type for normal every day driving is the diaphragm type pressure plate. The diaphragm type pressure plate has a single spring on it to load the pressure plate on the clutch disk. This single spring is a Bellville-style spring and will load the pressure plate evenly. This is because it works by applying pressure to the whole pressure plate assembly at the same time. Applying pressure to the whole pressure plate assembly gives it an advantage over the other two types of pressure plates. Also, when a Bellville spring is used it allows for less pressure to be applied to the clutch pedal when the car is at a stop which is a major advantage. The newer diaphragm type pressure with the Bellville spring now have weights attached to the fingers on the spring so it can provide a centrifugal load which helps the clutch hold the power better.
If a pressure plate is in need of replacement you should also replace the bell housing ball stud, throw out bearing and ball stud. You can find the three different types of pressure plates for sale in local auto supply stores and on various car part websites on the internet. You can also find diagrams of the different clutch pressure plate types online as well. If you are replacing or installing a new clutch system in your vehicle you can find lots of useful tips and advice on installing the pressure plate. If you are not sure which type is best for your vehicle don’t hesitate to speak with a professional in the car parts industry for advice.
