We recently installed the LEED Brakes’ manual front disc brake conversion kit (FC2002-C05) on a 1968 Plymouth Road Runner. The results were nothing short of impressive. LEED Brakes offers a conversion kit designed for easy installation, reliability, and braking performance for your classic Mopar. LEED Brakes has been in the aftermarket brake industry since 2004 providing top-tier components. They are dedicated to providing car owners with knowledge and support needed to perform safe and effective installations.
This 1968 Plymouth Road Runner has been owned by the same family since the ’70s. Originally, the car was QQ1 Blue and was repainted in Porsche Tabbot yellow. Under the fiberglass A12-style hood is a 383 with a Six-Barrel carburetor setup. Sporting a 4-speed manual transmission and four wheel manual drum brakes in dire need of an upgrade, which is what we are doing today. The wheels are a 15-inch Keystones which the brake kit will fit inside of.
Above: LEED Brakes’ manual front disc brake conversion kit (FC2002-C05) for B-Body Mopar with factory drum brakes.
This particular brake kit, designed for B and E-body Mopars, is the perfect solution to upgrade manual drum brakes to disc brakes. In our case, we chose the manual kit for two key reasons: with our road course racing experience, we prefer the feedback that manual brakes provide, and the fact that this Road Runner’s 383 engine doesn’t produce enough vacuum to operate a brake booster effectively. That being said, LEED Brakes does offer a power brake option with a vacuum pump if power is a better fit.
Everything you’ll need to install the brakes onto the original drum brake spindles is included. There is no cutting, drilling, or welding required, making it a straightforward, bolt-on upgrade. The components are precision machined, ensuring high quality and a factory-like fit. The kit includes 11.33-inch cast iron rotors. We choose the smooth version, though drilled and slotted options are available.
The four-piston calipers are made from cast iron and give an original appearance. Stainless steel pistons have zinc plating. The calipers come in a natural finish, red, or black colors. For future maintenance, a few clips hold the pads in and can easily be replaced. The calipers come preloaded with semi-metallic brake pads.
Above left: Shows all the hardware supplied in the brake kit. Above right: The new rotors are right hand threads. New lug nut maybe needed.
Above left: The new four piston calipers come preload with pads already installed. Above right: the new master cylinder has a bigger reservoir to hold more brake fluid. This is needed because a caliper requires more fluid then a wheel cylinder to operate.
The dual bowl master cylinder has a 15/16 bore and 4-bolt flange a lot like the factory, specifically designed for manual brake system (but there is a 1-inch bore option). Brake lines and all necessary hardware for a complete installation like clips, wheel bearing, cotter pins, shims, brackets, bolts, and caps are included. This kit is designed to fit most 14-inch wheels, so the 15-inch Keystones will fit fine.
Before we installed the brakes, we did a series of brake tests consisting of hitting the brakes at a specific point and speed. In this case, the speed was 65mph with an average stopping distance of 128 feet. After the new brakes were installed, we went ahead and did the same tests. Spoiler alert the results were mind blowing!
As for the installation process, we started off with the master cylinder. Removing the brake lines and being sure to lay some sort of catch can or rags under the master cylinder to catch any brake fluid, so no damage is done to the paint. It would be best to drain as much fluid out of the master cylinder as possible before starting. Removing the bolt from the pedal to master cylinder and the four bolts holding the master cylinder to the firewall will allow you to remove the master cylinder from the car.
Above left: A cover is placed under the master cylinder, before removing brake line, to prevent brake fluid from getting on the paint. Brake fluid is very corrosive. Above middle & right: Master cylinder mounting nuts, and push rod bolt are removed so master cylinder can be removed from fire wall.
Above left: The push rod and mounting bolts must be transferred to the new master cylinder. Above middle: We bench bleed the master cylinder to get out as much air before mounting. This makes it easier to bleed the entire brake system at the end. Above right: It is best to use a line wrench to prevent rounding off the nuts for the brake lines.
Before installing the new master cylinder, we bench bled it to get any air out of the system. The push rod and the mounting bolts had to be transferred from the old master cylinder to the new master cylinder next. The master cylinder is installed in the reverse order of removing the old one. All of the old lines fit directly into the new master cylinder and the push rod was also the perfect length.
We put the car up on a lift to start removing the front brakes. We removed the 15-inch Keystone wheels and the drums so we are able to access the nuts and bolts holding the backing plate to the spindle. Also, very important at this point, place a jack under the lower control arm and loosen the torsion bar.
When loosening the torsion bar, you can either count the turns or make a mark with a crayon or marker so it goes back in the original position. Loosening the torsion bar will allow the lower control arm and ball joint to move around freely so you can remove the backing plate and install future components. With everything removed we cleaned up the spindles.
Above left: With the wheel off we can access the drum and the nut to remove, both hub and drum together. Above middle & right: With the drum and hub removed, we can now remove the four bolts holding on the baking plate on to the spindle. loosen the torsion bars and support the bottom of the control arm. The two lower bolt hold the ball joint and spindle together.
Above left: The caliper bracket is installed with the supplied hardware. The brackets must be facing towards the front of the car. Above right: A chamfered spacer is supplied, and must be installed with the chamfered side in towards the car.
With the brake hose removed along with the backing plate and wheel cylinders, we used a tool to seal off the brake line so we don’t make a mess; you could also do this by placing a rag or catch can under the brake line.
With the spindle cleaned off, we can now install the caliper bracket which must face forward according to the instructions on both sides. The bracket will be installed using the supplied nuts and bolts, one of the lower ball joint bolts will need to be reused. A spacer goes onto the spindle first making sure that the chamfered edge goes towards the inside of the car. We pack the bearings with fresh grease and install them into the hub of the rotor with a new seal.
A note worth mentioning: if your car still has reverse-threads on one side, these rotors change these so you will need to get new lug nuts. We installed the proper washer and nut tightening down in the proper sequence and installing the cotter pin before installing the dust cap. We spin the rotor to make sure that there is no rubbing or abnormal drag.
Above left: New wheel seals, and bearing are supplied and must be packed with grease. Above right: The Spindle nut is torqued to 20ft lbs while spinning the rotor, then backed off and retorqued to 12ft lbs, while aligning the cotter pin hole.
Above left: Spacers are needed to install and align the caliper with the rotor. Above right: Make sure the bleeder screws are facing up or bleeding will be difficult. The caliper will be torqued to 45-60ft lbs.
Next we installed the brake calipers, which already come preloaded however we did not see any lubricant on the slides, so we disassembled the pads to lubricate these points. Make sure the caliper is mounted with the bleeder screws facing up, otherwise bleeding the brake will be very difficult in the future steps.
There are two spacers that go between the caliper bracket and the caliper itself that will set the position of the caliper on the rotor. Verify that the rotor is centered inside of the caliper; if not, other shims may be required. In our case, it was perfect, so we torqued down the bolts 60-foot pounds per the instructions.
New brake hoses were supplied in the kit with new copper washers and a clip to hold it to the original bracket on the frame rail. In our case, the brake lines threaded directly into the hose. The kit does come with fittings in case you have a different size. To help control the rear brakes we installed an adjustable proportioning valve.
Above left: A proportioning valve is supplied in the kit, with out this the rear brakes can lock up. The valve allows the pressure to the rear to be adjusted. Above middle & right: The rear brake line coming from the original proportioning valve, will be removed to allow the adjustable valve to be mounted.
Above left: The master cylinder is filled with DOT3 brake fluid, and continued to be filled as we bleed the brakes. Above right: With everything mounted, clearly there is plenty of room between the caliper, rotor,and wheels.
This valve will be installed between the original proportioning valve and the rear brakes. Using a line wrench, the original brake line was removed from the proportion valve and threaded into the adjustable valve. A short brake line was supplied in the kit which will fill the gap between the two proportioning valves.
After everything was installed, we went ahead filled the brake system with DOT3 brake fluid and bled the brakes. We allowed the system to gravity bleed by opening the brake caliper bleeder screws and leaving the master cylinder open until it started to drip, then closed the screws. After all of the air was bled out of the system, we did a few test stops to adjust the proportioning valve to the rear of the car.
After we made sure that the brakes were bedded in properly, we went to do our brake testing again. Performing the brake test at the same position and the same speed, the car stopped an average of 65 feet. That is 63 feet shorter than the original 128 feet which is a huge improvement. With the LEED Brakes conversion, the Road Runner stops more confidently and braking distances are significantly reduced.
David…just to be clear the, the rear drum brakes were retained? Had there been a disc brake package installed on the rear itself, it would require a 4wh disc master as well? No adjustable proportioning valve would be required?
Mike
Is the hub diameter for the wheel the same as original so that the wheels are still “hub-centric” instead of “lug-centric”?
Whats the Piston Diameter of those Calipers?