1968 Chevrolet Nova CPP Four-Wheel Disc Brakes - Disco Tech
Our ’68 Nova gets a big boost in stopping power with a set of CPP four-wheel disc brakes
From the July, 2011 issue of Popular Hot Rodding
By Stephen Kim
Photography by Johnny Hunkins
A set of drums can go a very long way if you happen to be a rock star, but face the facts. You’re not Tommy Lee. Besides, since there’s no modern equivalent of a ’80s Heather Locklear, the benefits of drums aren’t what they used to be, even for rock stars. For the average hot rodder, the only set of drums at your disposal are the ones bolted to your project car’s rearend housing, or gulp, to the front spindles. In either scenario, drum brakes aren’t a good thing. It wasn’t so bad back in the ’60s, when every other car on the road relied on such archaic technology, but the only thing you’ll out-stop these days with a set of drums is an 18-wheeler. Although most cars on the road today are mired in a perpetual state of plastic lameness and bear no semblance of performance, if your drum-equipped muscle car happens to be behind one of them as they stomp hard on the binders, you’re going to be in some serious trouble. Throw a ton of extra horsepower into the equation like we did with our ’68 Nova project car, and the problem becomes exponentially worse. Fortunately, Classic Performance Products has the perfect fix, and we were able to address the situation with a sweet four-wheel disc brake setup without breaking the bank.
Many aftermarket front disc...
Many aftermarket front disc brake conversion kits use C5 Corvette calipers, but CPP takes things one step further. CPP’s big brake kit uses PBR twin 52mm piston calipers as opposed to the 40mm pots used in the C5 calipers. Additionally, the CPP calipers are stiffer than the stock Vette units, and feature pads with a larger surface area. The end product is up to 50 percent more stopping power over the stock C5 hardware.
All brake systems serve the same purpose of converting kinetic energy into thermal energy, or heat. Seal the friction material and wear surfaces off from ambient airflow in a big iron chamber like a drum, however, and the braking system’s ability to dissipate heat is greatly diminished. Furthermore, as disc brake systems have become universal over the years in newer cars, our driving habits have changed accordingly to take advantage of today’s shorter stopping distances. As driver’s now accustomed to the stopping power of late-models, stepping on the whoa pedal in a muscle car with drum brakes can feel downright treacherous. Our ’68 Nova was one of the worst offenders out there, as it came equipped from the factory with drums on all four corners. “The stock drum brakes on the Nova were just flat-out dangerous,” Hunkins says. “When you hit the brakes, you never knew if the car was going to pull to the left or to the right. It was a chore just to keep the car going straight even when stopping normally. I’m surprised I didn’t wreck the car before upgrading to the CPP discs.”
The good news is that disc brake conversions are now so common that you can get some serious hardware for not a lot of money. Likewise, the popularity of disc brake swaps means that installing them no longer requires proficiency with a plasma cutter and MIG welder. CPP has assembled an entire catalog of parts with affordability and bolt-on simplicity in mind, which meshed perfectly with our Nova’s overall theme. The goal with this project is to build a car that can accelerate, turn, and stop as well as a C6 Corvette using affordable parts that anyone can install in their driveway. To that end, we’ve already installed a Dart-based 400ci small-block good for 523 hp, and a complete CPP front and rear suspension. What makes CPP’s big brake setup so appealing is that it boasts 13-inch cross-drilled and slotted rotors up front with two-piston calipers all for $999. That price includes a set of 2-inch drop spindles, hubs, caliper brackets, and brake hoses. CPP offers the same kit without the drop spindles for $200 less. The rear disc setup consists of 12-inch rotors, single-piston calipers, mounting brackets, new hoses, and all necessary hardware for $699. Due to the inherent similarities between X-bodies and F-bodies, either of these brake kits will fit both ’68-74 Novas as well as ’67-69 Camaros. Finally, to get the most out of the new front and rear discs, we matched them up with a new power brake booster as well. So for just a hair over $2,000 we transformed the braking ability in our Nova from horrendous to heroic in one afternoon. Thanks to Craig Chaffers and the crew at CPP for inviting us over to their shop and turning the wrenches.
|Front disc brake kit
|Rear disc brake kit
|Power brake booster
|Stainless brake lines
The CPP big brake kit is compatible...
The CPP big brake kit is compatible with the company’s 1045 forged steel 2-inch drop spindles, or the stock spindles. The drop spindles had already been installed on our Nova as part of a complete front suspension overhaul. In addition to the reduction in ride height, the drop spindles eliminate the need to grind the stock units for clearance.
The new wheel hub assemblies...
The new wheel hub assemblies that come with the CPP brake kit include a set of wheel studs. Before sliding the hubs onto the spindles, the inner bearings were packed with grease. Afterward, using a flat piece of steel, the bearing seals were tapped flush to the hubs.
Before installing the hubs,...
Before installing the hubs, the caliper brackets were bolted to the spindles. Next, the hubs were placed onto the spindles, and the outer bearings were pushed into the hubs. Each assembly was then cinched into place with a castle nut using a 11⁄16-inch socket. It’s imperative to resist the temptation to crank down on the castle nuts with a big breaker bar. Since the hubs must rotate freely on the spindle, the correct torque spec is a mere 15 in-lb. With the nut torqued, Craig Chaffers installed the cotter pins and dust caps.
After positioning the rotors...
After positioning the rotors on the hubs, the calipers were bolted down to the brackets using a 13⁄16-inch socket. Next, the worn stock rubber hoses were replaced with the new CPP units, and attached to the calipers with new banjo bolts. Unlike a fixed caliper, a sliding caliper positions all the pistons on the inboard side of the rotor. The benefit is increased wheel clearance, and the CPP calipers fit inside the Nova’s 17-inch rollers with room to spare.
The comprehensive rear brake...
The comprehensive rear brake kit fits both 10- and 12-bolt rearends and includes 12-inch drilled and slotted rotors, single-piston calipers with an integrated parking brake, caliper brackets, shims, hard lines, hoses, and parking brake cables. The rotors aren’t small by any means for a typical street machine, yet the entire brake package will fit inside most 15-inch wheels. Considering all that’s included, it’s tough to cobble together a similar setup for less than CPP’s MSRP of $699.
Due to the various widths...
Due to the various widths of factory and aftermarket rearends, the CPP kit comes with a stack of 1⁄8- and 1⁄16-inch shims to properly locate the calipers over the rotors. Chaffers used a 1⁄8-inch shim to move the caliper brackets off of the bearing face to simulate the thickness of the stock drum brake’s backing plate.
With the shims in place, the...
With the shims in place, the caliper brackets were bolted to the rearend housing using four through-bolts and 9⁄16-inch nuts. Since the rotor hats are 1⁄8-inch thicker than the stock drums, the CPP kit includes longer wheel studs. Installing them on a stock rearend involves removing the axles, but since our Moser 12-bolt was already equipped with longer studs, we skipped this step.
With the rear rotors positioned...
With the rear rotors positioned onto the axles, the calipers were bolted to the brackets with a pair of ¾-inch bolts. This process may need to be repeated several times to establish proper pad-to-rotor clearance.
To prevent uneven pad wear...
To prevent uneven pad wear or excessive drag, an equal amount of clearance should be between the inside pad and rotor, and the outside pad and rotor. After bolting down the calipers for the first time, the gap on the inboard pads were found to be much larger. To even up the gap, Chaffers installed a shim between the brackets and calipers.
The last step in the rear...
The last step in the rear brake installation is attaching the parking brake cable and rubber brake hoses. Another very nice touch in the CPP setup is that it includes a nifty band clamp with a mounting tab that wraps around the axletubes. This holds the hose in place and eliminates the need to weld a mounting tab to the rearend.
To maximize stopping power,...
To maximize stopping power, we opted for a CPP power brake booster and master cylinder assembly. Removing the stock hardware is as easy as unbolting the pushrod clevis from the brake pedal, disconnecting the brake lines, and detaching the booster from the firewall. The new 11-inch CPP unit drops right into place. It includes an integral distribution block, and a hydraulically actuated brake light switch.