Brake-Away Installing C6 Z06 Brakes on a C2 Corvette

Posted on June 3, 2015 by Jefferson Bryant in Issues, Projects, STM Staff, Suspension, Tech // 0 Comments

The C2 Corvette, also referred to as a Mid-year, is the most popular body style of Corvette. Built from 1963 through 1967, the C2 short run of this body style is certainly not hampered by lack of aftermarket support, part of the reason is that the C2 shares its chassis with the C3 Corvette. While the C2 and C3 models had 4-wheel disc brakes (beginning in 1965), the world of brake technology has greatly improved over the last 50 years.

Forty-two years later, Chevrolet rolled out the C6 Corvette, and in 2006, the Z06 package was released. Among the upgrades were the legendary dry-sump LS7 and massive 14-inch disc brakes with 6-piston calipers in the front and 13-inch discs with 4-piston calipers in the back. These brakes are capable of reining the 3,130-pound C6 from its 198-MPH top speed to 0, making them perfect for a swap to the C2/C3.

Speed Direct, the makers of the Steeroids rack and pinion conversion and Shark Bite coil-over suspensions for C2/C3 Corvettes, has a bolt-on kit that uses the GM factory C6 Z06 calipers along with custom 13-inch rotors for Corvettes built from 63 (63-64 require later spindles) up to the 1982. Aside from the obvious appearance upgrade, the Z06 package brings modern performance to these cars. While you may not be topping out the speedometer with 250-300 horsepower, engine swaps and power adders increase the overall speed potential, and the factory brakes start leaving a lot to be desired.

The original disc brakes for the C2 used 4-piston calipers with a wide brake pad. As the brakes are applied, there is a tendency for the pads to wear unevenly. This means that the brakes lose stopping power, eventually fading away. Additionally, the smaller 11-inch solid rotors retain more heat, and heat is the true enemy of braking performance. Upgrading to the Speed Direct Z06 package changes the situation drastically. Instead of a single wide brake pad on either side, you get 6 pucks made from a special ferro-carbon material from Hawk, specifically the Hawk HP-plus. These pads dissipate more heat than standard pads and bite harder, which means consistent performance on and off the track. These pads generate a little more dust than ceramic pads, but have superior bite. Ceramic pads are readily available for the Z06 calipers.

With 6 pistons pushing on 6 individual pads, the friction surface is greatly improved, along with even pad and rotor wear. The superior calipers and pads are only half of the equation, as they must have something to clamp onto. The larger the rotor diameter, the more torque force is available to stop the vehicle. Think of this like a wrench, the longer the handle, the more leverage you have to move the bolt. Brake rotors work in much the same manner. The thickness of the rotor is also important, as the heat absorption and dissipation rates vary based on the thickness and design of the rotor. The Speed Direct Z06 kits use custom-designed rotors in three versions: solid, slotted, and cross-drilled with chamfered holes to prevent stress fractures.

The one main caveat for this brake upgrade is that with larger rotors and calipers comes a need for an increase in wheel diameter. The Z06 kit requires a minimum of 15-inches of inner wheel diameter. This means a 17-inch wheel or larger. So while you can’t run the factory wheels, most builders interested in this type of upgrade will already have, or be looking at larger wheels.

The factory master cylinder is capable of operating this system, in either power or manual versions, making this a simple conversion. The kit comes with new stainless steel braided brake lines, all the brackets, and fasteners needed for the kit. The entire kit, front and rear, installs in less than a day. The front system is more involved, as some cars still have the rotors riveted to the hubs. The rivets will have to be drilled out before the new rotors are installed.

We installed one of these systems on our 1966 Corvette coupe, and the results are staggering. Not only does it look amazing, the car has modern sports-car performance. This Corvette build project started out as a basket case, so we were not able to get before performance data, but the Vette stops without much pedal effort (power assisted), no squeal, no grabbing, and there is no brake dust dirtying up the Weld Racing S77 wheels. Adding C6 Z06 braking performance to a 50 year old Corvette? Easy as pie.

01. The Vette came to the Red Dirt Rodz Studio in pieces, so we don’t have much in the way of disassembly pics. The front rotors still have the hubs riveted in place, so those were drilled out on the drill press. This takes patience, use several sized drill bits, stepping up as you go. Once the rivets are drilled out, use a hammer to knock the hub out of the rotor.

02. We painted the hub with some Eastwood Rust Encapuslator and left it to cure.

03. The Speed Direct Z06 brake kit comes with everything you need to install it. We opted for the chamfered cross-drilled rotors for killer looks and track-ready performance.

04. The project began up front, where we removed the original caliper bracket. There are two bolts holding this in place. Usually there are dust shields between the spindle and the bracket, but as we said, this car had been taken apart before. We used an Ingersoll Rand cordless impact to make quick work of the bolts.

05. You can see the difference in the old bracket (left) and the new machined bracket (right). These are side-specific, so make sure you keep them straight.

06. Dust shields are not used for the fronts with the new brake kit. The machined bracket bolts to the spindle using the original hardware.

07. The upper bolt is torqued to 180-foot pounds, while the lower bolt receives 120-foot pounds of torque.

08. Next, we reinstalled the hub to the spindle. This is a good time to replace the wheel bearings. The bearing preload needs to be 12 foot pounds. Be sure to rotate the hub while tightening the spindle nut to seat the bearings.

09. The kit uses a pair of spacers on two of the lug studs. These are there to locate the rotors to the hub, don’t leave them out. Next, slide the rotor over the hub and secure with a lug nut.

All four calipers come unassembled. We installed the lugs for the brake pad pucks and then loaded the pucks into the calipers. The lugs keep the puck’s movement square to the rotor, reducing noise and chatter.

11. These calipers have 3 ports for the brake lines. An adapter installs into the center port, the two outer ports are used for the air bleeds. This fitting requires a copper or aluminum sealing washer.

12. In order to get the most out of your braking system, the calipers must be centered over the rotor. Every car is different, so the kit comes with a set of shims. These shims pull the caliper towards the engine. Our car needed three on both sides. A little dab of grease on each one helps hold them in place for installation.

13. We dropped the calipers over the rotors and threaded in the 14mm bolts and lock washers to the caliper bracket. These bolts were torqued to 120 ft. lbs.

14. The factory brake line connector was removed from the frame and the new adapter installed with a new spring clip. The braided steel hoses then thread onto the new adapter.

15. Next, the other end of the line was attached to the caliper. We repeated these steps for the driver’s side brakes.

16. All done for the front, now we need to install the rear discs.

17. The rear brakes are fairly simple, but there is cutting required. The factory emergency brakes are located inside the rotor hub, those are left untouched. First, we measured two inches of the forward-facing dust shield.

18. This line shows where we are going to cut. This is for clearance of the caliper and bracket. Removing this dust shield requires disassembling the entire rear drive, so cutting it is the best method.

19. We used a cut-off wheel to slice through the shield. This will get touched up with a little rattle-can paint to keep it from rusting. The e-brake mount may need to be bent down. If you have Van Steel offset trailing arms, the mount will need to be bent quite a bit.

20. The rear bracket bolts to the same ears as the factory caliper. You can install these on the wrong side; the recesses for the caliper should face the outside of the car.

21. The Van Steel Trailing arms are a little larger than the factory arms. We had to grind a half-moon on the bracket in order to get the clearance needed.

22. Once the bracket cleared the trailing arm, they were bolted to the arm. These bolts were torqued to 70 foot pounds.

23. We slid the new rotor over the hub. There are alignment holes in the hubs for the e-brake adjustments. Make sure that these are lined up with the hub.

24. The kit comes with an adapter fitting for the rear brake line to thread into the factory brass line blocks. The rear kits use a new stainless steel braided flex line as well.

25. A banjo-style fitting is used on the rear calipers to keep the line out of harm’s way and for ease of installation. Banjo fittings use two aluminum or copper sealing washers—don’t forget those.

26. The rear brakes are now finished. The system must be bled before driving the car. Always start at the furthest point from the master cylinder and work to the closest.