Courtesy the Manufacturers
July 18, 2011

One of the pros of using a hydraulic clutch system is that the pedal pressure can be fine-tuned. Since you're essentially using two hydraulic cylinders to actuate your pressure plate, you can change those ratios to give you the desired result. Typically, a large master cylinder pushing on a small slave cylinder will give you a harder/firmer pedal, with a shorter pedal stroke required to actuate the clutch. When you decrease the size of that master cylinder piston, you decrease the amount of pedal pressure required as you're pushing on a smaller piston area.

However, the amount of stroke required to accomplish the same task increases. So, if you have a 3,000-pound, hydraulically actuated pressure plate and you find yourself needing to go to the gym to push the pedal down, try a smaller master cylinder. It can make a huge difference, even going from a 7/8-inch master cylinder bore to a 3/4-inch master cylinder bore. The downside to hydraulic systems is that they're comparatively more expensive (especially where hydraulic release bearings are concerned), they're messier to deal with (the systems rely on brake fluid and the lines must be bled), they require firewall strengthening on older vehicles, and if you ever have a hydraulic release bearing failure, you can count on removing the transmission and possibly the bellhousing to replace it.

In terms of "what will work with what," as long as the components are correctly specified, you can run different styles of clutches on different vehicles. With all of the aftermarket parts available by different manufacturers, you can run a mechanically actuated, diaphragm-style clutch in a '69 Mustang with a 1-3/8-inch Top Loader, or you can run a cable actuated, long-style clutch in a '93 Mustang GT with a T-5.

Again, careful consideration must be given to several different specifications, including where the clutch fork pivot is located, the diameter of the release bearing face, the bore in between the pressure plate fingers, and even the bellhousing that you are using. There are very common combinations to be used with each style of car, but clutch kit components can be mixed if a different route needs to be taken.

Hopefully, we've armed you with a little more information on how to choose your own clutch kit. The task can be daunting at first, but once you get a feel of what you really want to do with the car, what you're able to sacrifice in terms of streetability, and what's available in the aftermarket selection of parts, then you can make a very educated decision on the kit that you need between your engine and transmission.

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