These master cylinders are manufactured with an aluminum body along with a relatively large capacity plastic reservoir with dual outlet bores (which correctly face the driver side fender when mounted in the car). If there is a shortcoming to this master cylinder design, it's the size of the outlet fittings. The front fitting is a 9/16-20 Inverted Flare while the rear is a 1/2-20 Inverted Flare. Unfortunately, it's difficult to find appropriate adapter fittings for these flare dimensions. Lamb Components does offer a solution. They manufacture special #3 A-N male adapters specifically for these master cylinders (these Lamb fittings are relatively inexpensive and a real frustration-saver). FYI, the master cylinders sold by Mark Williams can have these Lamb fittings installed as an option.

You'll also find that these master cylinders will require an adapter to fit the firewall on most vehicles. These adapters are designed to convert something such as a later model Firebird (which originally came equipped with a power booster) to the manual, Mopar pattern. Lamb Components offers several different adapters for varied applications and so does MPR (see the source box for more information).

You'll also find that these master cylinders will require an adapter to fit the firewall on most vehicles. These adapters are designed to convert something such as a later model Firebird (which originally came equipped with a power booster) to the manual, Mopar pattern. Lamb Components offers several different adapters for varied applications and so does MPR (see the source box for more information).

Pedal Pushers

The pedal ratio is critical. What's pedal ratio? The brake pedal acts as a lever to increase the force you (the driver) apply to the master cylinder. In turn, the master cylinder forces fluid to the disc brake caliper pistons or drum brake wheel cylinders. If you examine a brake pedal, you'll see the pivot point (where the pedal swivels) and the mounting point for the master cylinder pushrod are usually different. By varying the length of the pedal, and/or the distance between the pushrod mount and the pivot, you can change how much force (from your leg) is required to energize the master cylinder. This is the "mechanical advantage" or pedal ratio. This formula will help you figure it out:

Input Force X Pedal Ratio = PSI   Brake Piston Area

Translated, this is the amount of force exerted by your leg times the pedal ratio divided by the area of the brake piston(s). The typical adult male can exert approximately 300 pounds of force with one leg. If you've ever tried leg presses at a gym at 300 pounds, you'll know

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hat's a bunch. Something in the order of 1/3 or 1/2 that figure is obviously more comfortable, even in a racecar. Of course, you also use the brakes to stage the car, and in some cases, racers "pump" the pedal in an attempt to increase holding power. But does this actually increase the brake line pressure? According to Mark Williams, this practice doesn't really change the pressure. If you have to pump the pedal to increase the holding power of the brakes, something has pushed the pistons back in the caliper (run out in the rotor, a cocked caliper, bad mounts are all examples). Another common cause is air in the system. Bottom line? If you have to pump the brakes to hold a car on the starting line, something is wrong. Pumping the pedal does not build pressure, although it might eliminate pedal travel.