Pictured at the top is a GM caliper ('78 and later featured a single piston 2 1/2-diameter bore), and it is a self-centering, floating-style caliper. It slides on two bolts that go through the ears on the outer ends of the housing . The single piston makes it self-centering on the rotor and gives equal pressure to both sides of the rotor. The bottom caliper is a (1 3/4-inch bore) four-piston Wilwood, non-floating caliper, but since both reservoirs are connected, equal pressure is exerted on both sides.

Real stainless braided hose has an inner Teflon tube that is non-collapsible, or expandable under severe-use conditions. Make sure your hoses are DOT approved (department of Transportation). The threaded collars do not allow the line to twist during installation. The two items on the right are both in-line check valves. They are available in a variety of different ratings.

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If your component diameters (master cylinder, rotor diameter, caliper diameters, etc.) fall within our discussion of component diameters in this article and your pedal is too hard and the car doesn't stop very well, decrease the master cylinder bore diameter.

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To get more force at the front calipers or tear wheel cylinders, increase the bore diameter (without changing the master cylinder, or any other components). More piston area (at the wheels) equals more pressure.

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Larger diameter rear tires act as a lever and more braking is needed than with a stock tire diameter. This situation (big 'n littles) also brings the weight more to the front of the car.

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Proportioning valves alter the rate of pressure rise.

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Residual pressure valves are needed at the master cylinder when using drum brakes and wheel cylinders.

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If you remove the residual check valve from the master cylinder, you must have at least a 10 lb. (psi) check valve in the line, between the master cylinder and the drum brakes.

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To increase pressure from the master cylinder, use a smaller diameter master cylinder bore. RULE OF THUMB: Following the component diameters and weight bias discussed in this story, manual brakes in a street rod can have a one inch or smaller diameter master cylinder bore, while power brake systems can have one-inch or larger (increase or decrease bore diameter by 1/16 or 1/8-inch). Since hydraulic pressure can always be manipulated, there will be variations to this rule of thumb.

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Master cylinders with a one-inch and larger bore will give a stiffer feeling pedal, however it will deliver less pressure than a one-inch and smaller diameter bore.

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Master cylinders with bigger bores give less pedal travel, yet a firmer feeling pedal, while a smaller diameter bore will yield more pedal travel and give a softer feeling pedal.

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The higher the pedal ratio, the more travel. RULE OF THUMB: It's common in street rods to have a 5:1, or 6:1 pedal ratio. Example: a brake pedal pad (on the brake pedal arm) 10 inches from the pivot with a master cylinder arm two-inches long (from the pivot) would give a 5:1 ratio.

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Stainless hard lines (and AN fittings) have 37 degree single flare, while SAE steel hard lines have a 45 degree double flare.

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Available in all NAPA parts houses is a DAYCO (vacuum only) hose with a special heavy reinforced wall, DAYCO part number 800944. Ask for the 11/32-inch i.d. (vacuum only) brake hose.

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In a hard braking situation, when the weight has shifted, more of the braking has to be done by the front brakes.

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There are two most commonly used types of calipers on street rods: Floating and non-floating. Example: All Jag rear ends use non-floating (Girling) calipers, and the majority of Wilwood calipers used on street rods are also non-floating. They are precisely centered over the rotor when bolted to the bracket.

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Ford and GM single-piston, floating calipers are self centering and offer equal pressure to each pad, while non-floating calipers (like most Wilwood and Jag) are not self centering and offer equal pressure to all pads when the hydraulic reservoirs are connected, internally or externally.

C.H. Topping & Company
520 W. Esther St., Long Beach, CA 90813
(562) 432-0901
email: chtop@earthlink.net