CH TOPPING & CO. Performance Brakes since 1931
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Cooling Your Calipers
By Larry Saavedra

The faster you go, the faster you need to stop. There is no disputing that high-performance cars like the IROC destroy brake I ads, rotors, and calipers quicker than any economy car does. A Z/28 weighs quite a bit, which greatly speeds the wear of brake pads on the bigger car. Also, what Corvette driver can resist testing the torque of his car-only to decelerate in the same dramatic fashion?

This translates to excessive heating of the braking system, which is one cause of "brake fade." Heat can also break down the structural integrity of the hardware.

When brake discs and drums get hot, a vapor builds up, either between the drum and the shoe or the caliper and the rotor. It's like putting two magnets together: the gas prevents the pad or shoe from making full contact with the--rotor or the drum.

One solution that puts a freeze on brake fade is vented rotors or drilled rotors/drums. But these new rotors and drums must be accompanied by performance pads and related components for you to actually notice significant effects.

Drilled rotors (and sometimes drums) are popular in motorsports, where vehicles accelerate and decelerate at high rates of speed. You've probably seen drilled rotors on road racing motorcycles, and some NASCAR drivers rely on drilled rotors as well. The drilling of small holes in the rotor allows the air to flow through the caliper and escape.

Pre-drilled rotor and drum kits are available, but never attempt to drill a rotor or drum yourself. Improper venting of drums and rotors can cause imbalance or breakage of these components. In the worst case, it can lead to serious injury if the part fails.

One of the leading innovators of this procedure is Vince Bunting of C.H. Topping & Co., a specialist in the field of high-performance brakes.

"One of the great things about venting brakes is that you can get more than 50 percent longer brake life," he said. "A lot of off-road drivers prefer vented rotors and drums because the holes actually will throw out sand and water by centrifugal force. Vented rotors and drums also help release brake dust build-up."

C.H. Topping & Co. was understandably a bit hesitant to divulge much information about the process. But it's safe to say that the drilling process begins with either the drum or the rotor. The pattern of these holes varies, but the entire diameter of the drums and rotors is covered.

Imagine a chalk line drawn along the inside of a drum and circles on the face of the rotor. The drilling would touch every line at a specific point. Moreover, left and right drums and rotors have different patterns of ventilation. The diameter of the holes also varies from vehicle to vehicle.

To better understand the benefits of drilled rotors/drums, we took our 1985 IROC Z/28 Camaro to C.H. Topping, who performed its complete package as we photographed the process.

First, the IROC was lifted on a hoist, and the wheels were removed. Vince and his assistant, Tom Kor, immediately got to work removing the front rotors and rear drums. Once Tom finished cleaning the backing plate on the rear drums with solvent, he inspected the cylinders. Tom pointed out that the rear wheel cylinders needed rebuilding because the rubber seals were worn. "That's a common problem with these cars," he said. "Once these seals go bad, the fluid leaks down into the shoes."

Tom suggested that the brake lines be periodically checked for leakage as well. Then the rotors and drums were taken to be drilled.

Each drum and rotor took approximately 30 minutes to drill. When they were finished, the rotors were taken to another work bench, where the holes were countersunk so that the face surface remains smooth. The drums were "turned" on a special lathe.

Next, Tom began work on the front pads and rear shoes. Bendix metallic brake pads were installed on the front and Bendix organic shoes on the rear. The high-performance metallic pads are installed on the front because 70 percent of your braking performance is generated from those brakes.

The time had finally arrived to test the IROC's new brakes on the open road. In a seat-of-the-pants evaluation, We drove the car along the California coastline. Outside of the Los Angeles area, as you head north, the coastline curves back and forth. The elevation rises, too. This constant braking and accelerating gave us a prime opportunity to test the drilled rotors and drums for overheating (brake fade). The first thing evident was the response. There was no lapse between stepping on the pedal and contact. No brake fade, either! The great thing about these new brakes was that water didn't seem to affect them.

The drilled rotors and drums were designed to expel water with centrifugal force. After negotiating a series of water traps along the coast, we were relieved to say the drilled rotors/drums performed as expected.

As an interesting note, the folks at C.H. Topping will handle out-of-state requests for drilled rotors/ drums. United Parcel Service is available. The cost ranges from $25 to $35 per rotor and drum, plus shipping and handling charges. It would be wise to call ahead before shipping any components.



C.H. Topping & Company
520 W. Esther St., Long Beach, CA 90813
(562) 432-0901