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Disc Brakes Made Easy: Dissecting Summit Racing’s Disc Brake Conversion Kits

Summit Racing Drum-to-Disc Brake Conversion Kit
Summit Racing Disc Brake Conversion Kit, Brake Calipers
Summit Racing Disc Brake Conversion Kit, Brake Rotors
Summit Racing Disc Brake Conversion Kit, Master Cylinder
Summit Racing Disc Brake Conversion Kit, Brake Spindles
Summit Racing Disc Brake Conversion Kit, Complete Brake Kit
Summit Racing Disc Brake Conversion Kit, Slotted Rotors
Summit Racing Disc Brake Conversion Kit, Spindle Kit
Summit Racing Disc Brake Conversion Kit, Complete Kit
Summit Racing Disc Brake Conversion Kit, Full Wheel Brake Kit

Horsepower and front drum brakes do not mix. But that’s what you often got when you bought a muscle car back in the 1960s, at least until the factories wised up and offered disc brakes around 1967. If your classic muscle still has drums up front, fix the factory’s mistake with a Summit Drum-to-Disc Brake Conversion Kit. The Complete Kit shown fits 1964-72 GM A-bodies, 1967-69 Camaro/Firebird, and 1968-74 GM X-bodies (Chevy Nova, Pontiac Ventura, Olds Omega, Buick Apollo). You get 11-inch solid rotors, calipers with pads, disc brake spindles, master cylinder, 9-inch power booster, proportioning valve, backing plates, bearings and seals, hose, fittings, and all necessary hardware. We’ll highlight the major components in this slide show.

The calipers are brand new single piston units, just like the ones GM used on zillions of cars from 1969 through the mid 1970s. The floating-style calipers slide on bolts at each end of the caliper housing. That allows the caliper to self-center on the rotor and apply equal pressure on both sides of the rotor. It’s a reliable, time-proven design that you can get rebuild parts for at virtually any auto parts emporium. The pads are semi-metallic compound ideal for street use. You can get high performance replacements from the brake manufacturers Summit Racing carries, including Wilwood, EBC, and Hawk.

The optional factory disc brakes offered by GM on the A-bodies, Camaro/Firebirds, and X-bodies had 10-inch diameter rotors. The solid rotors in the Summit Complete Kit are 11 inches in diameter. The extra braking area dissipates heat better, greatly reducing brake fade. The rotors are also vented to circulate cooling air around the inner surfaces, further improving stopping power.

The dual master cylinder, power brake booster, and adjustable proportioning valve come in the kit. The 9-inch diameter, aftermarket-style booster is a direct-fit and will clear most tall-style valve covers. The proportioning valve is designed for front disc/rear drum braking systems. Unlike OE-style valves that are fixed for a specific vehicle's weight and power level, the kit's adjustable valve lets you tailor brake bias to your car and driving style. If your car’s engine doesn’t generate at least 18 inches of vacuum (due to high compression or a long-duration camshaft), you will need to add a vacuum canister or pump to supply the necessary vacuum to the brake booster. If your engine is really hairy, you might consider using a Summit Full Wheel Kit (no booster or master cylinder) to convert to manual disc brakes.

Summit gives you brand new, OE-style disc brake spindles. Not only do you get the peace of mind of using new parts, you are also spared the time and expense of getting the old spindles machined to accept the disc brake components. The backing plates and caliper mounting brackets are all-new components as well.

Nothing is more frustrating than finding out you’re missing some little widget or doo-dad required to finish a job. You won’t have that problem with a Summit Complete Brake Kit. It comes with all of the nuts, bolts, seals, bearings, hose and line, and fittings required—even the dust caps are included.

You can get a Summit brake kit with upgraded slotted rotors like these. The CNC-machined slots help clean dust and residue off the pads, and also increase cooling airflow over the rotor surfaces. The rotors are not offered cross-drilled. Cross-drilling can cause severe stress fractures, shortening the life of the rotor and possibly leading to brake failure.

Looking to adjust your muscle car’s attitude along with improving its stopping power? Summit has disc brake conversion kits with 2-inch drop spindles. The rotors are 10 1/2 inches in diameter, required due to the decreased clearance inside the wheelwell. Stopping power is not compromised, though. The drop spindle brake kits are available for 1955-57 Chevy, 1964-72 GM A-body, 1967-69 Camaro/Firebird, and 1968-74 Nova/X-body. All kits can be ordered with slotted rotors.

Chrysler was one of the last to use front drum brakes; the factory made discs mandatory only on Hemi-powered B- and E-bodies into the early 1970s. But you can correct Ma Mopar’s oversight with one of these Summit brake kits. You can get the Complete Kit shown here, or a Full Wheel Kit that has all the stuff the Complete Kit has except for the master cylinder, power booster, and proportioning valve. Either kit requires the use of 15-inch wheels to clear the calipers.

If your car already has a power brake booster setup, or you want to go with manual disc brakes, consider a Summit Full Wheel Brake Kit. It has everything you need to convert from drum to disc, except for the master cylinder, booster, and proportioning valve. The kit shown here fits 1955-58 Chevys; it comes with special caliper brackets that fit on the factory drum brake spindles. We have Full Wheel Kits for GM A-body and X-body cars, first-gen Camaro/Firebird, and 1959-64 full size Chevys.

Back when our old cars were new, drum brakes were the standard. It wasn’t so much that drums were good at their job. They were familiar technology and more importantly, cheap. With lower horsepower levels, slower speeds, and less congestion to contend with, drum brakes usually gave drivers enough time and distance to come to a stop without plowing into somebody.

But when Detroit started adding more horsepower in the late 1950s and ’60s—and rodders piled more power on top of that—drum brakes made their inadequacies known. Long stopping distances, quick fading, and an unsettling tendency to lock up at the drop of a hat did not mix well with big horsepower. By the late 1960s, the factories figured that out and made front disc brakes standard equipment on their top-dog muscle cars and an option on many other models.

But what if you still have drums on the front of your vintage ride? No worries—you can have your horsepower cake and stop it too with a Summit Drum-to-Disc Brake Conversion Kit.

Does swapping out a whole brake system sound intimidating? It really isn’t. The Summit brake kits are designed to be direct bolt-ons. You get the rotors, new GM-style calipers with pads, spindles (1955-64 full size Chevys get caliper adapter brackets), backing plates, bearings, seals, hose and fittings, and mounting hardware. In most cases, the kits fit the vehicle’s existing hard brake lines.

The Summit disc brake kits are available in three versions:
The Full Wheel Kits include everything mentioned above. They are a good choice if you don’t need a master cylinder or power brake booster, or just want manual disc brakes.
The Complete Kits have all the stuff in the Full Wheel Kits plus a master cylinder, nine inch power brake booster, and an adjustable proportioning valve.
The Complete Drop Spindle Kits have all of the goodies from the regular Complete Kits, but have two inch drop spindles to give your car some extra attitude.

Summit Racing has Full Wheel and Complete brake conversion kits for the following vehicles:
• 1955-57 Chevy
• 1959-64 full size Chevy
• 1964-72 GM A-body, 1967-69 Camaro/Firebird, 1968-74 GM X-body (Nova)
• 1962-72 Mopar B-body, 1970-74 E-body

Select Summit brake kits can be had with 11-inch slotted rotors. The CNC-machined slots direct more air over the rotor faces, which cleans dust and junk off the brake pads and helps the rotors run cooler. And unlike cross-drilling, the slots will not cause stress fractures that can lead to rotor failure. The upgrade also comes with stainless steel braided hose that runs from the calipers to the factory hard line.

We’re going to dissect a Summit Complete Brake Kit for the 1964-72 GM A-body (Chevelle/Malibu, Tempest/GTO, Cutlass/442, Skylark/Gran Sport). Zillions of these cars came from the factory with drum brakes, which were marginal even when they were new. With today’s horsepower levels and insane traffic, disc brakes are practically mandatory.

And yes, Virginia, we have rear disc brake conversion kits too. The Summit Racing Rear Drum-to-Disc Upgrade Kits feature GM-style single-piston calipers with an integral parking brake, solid iron rotors, pads, and all the bracketry and hardware required. Kits are available for GM 10- and 12-bolt axles, Ford 8-inch and 9-inch axles, and Chrysler 8 3/4-inch and passenger car Dana 60s.

When an upgrade not only improves vehicle performance but also makes your car (and you) safer, it’s pretty much a no-brainer deal. So ditch those old-fashioned drum brakes for modern stopping power. You’ll be glad you did.

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