1971 Plymouth Satellite - Fast Brake
How To Upgrade Your Mopar's Braking System With Modern Hardware From Wilwood.
From the October, 2009 issue of Popular Hot Rodding
By Steve Dulcich
Photography by Steve Dulcich
Modifications to a performance car take on a variety of forms, and for traditional muscle cars the most obvious mods are those underhood contributing to the "go." Probably just as important are changes just a little further down that focus on the "whoa." Safety is just as much a concern here as performance, especially considering many cars of the era were factory equipped with barely adequate drum brakes. Our '71 Plymouth Satellite project was thankfully equipped with the optional factory front disc brakes, a system greatly superior to drums, but even here we saw plenty of room for improvement.
The factory disc brake system on our Satellite is certainly a product of the industrial age, a time when iron was as cheap as the dirt it was processed from, and weight was far from a primary design concern. All of that metal, a single-piston pin-mounted caliper, and an overall rotor diameter of 11 inches, made for a cheap and effective braking system for its day, but it was a system that is admittedly primitive in contrast to what is generally seen today. We definitely recognized the opportunity for an upgrade, with a goal of installing a system that is both better and lighter, adding to the braking performance as well as to the overall gains achieved though reduced weight.
Wilwood offers exactly the system we wanted: a lightweight disc conversion using a fixed caliper system, and larger diameter 12.19-inch rotors for improved mechanical advantage. We looked at our entire braking system and made the decision to re-vamp the whole thing, using Wilwood's "Dynapro 6" 12.19-inch, six-piston kit up front, and the "Dynalite Pro-Series" 12.19-inch four-piston kit at the rear. At the same time we would heave the heavy iron master cylinder and power booster, going to a manual system, and add an adjustable proportioning valve to allow tuning the front/rear brake bias.
Since the Wilwood kit is designed to retrofit factory drum brakes, replacing the front disc brakes on our Satellite required a swap to the drum brake spindle. We found the front brake swap to be a simple upgrade, and the weight savings were substantial at nearly 40 pounds total. With the bigger brakes, wheel fit was a question with our aftermarket 15-inch wheels. According to a source at Wilwood, the 12.19-inch brake system will clear some 15-inch wheels, but interfere with others, depending upon specific wheel design. We found our 15-inch forged alloy Cragars by Weld Wheels cleared.
Discarding the factory iron master cylinder and brake booster and converting to the Wilwood aluminum master cylinder required an OEM manual brake pushrod and manual brake firewall reinforcement plate. The Wilwood master has a two-bolt pattern rather than the four-bolt pattern used by Mopar until 1979, so we drilled our plate, firewall, and pedal bracket to match. Since the two-bolt late Mopar aluminum master cylinder is a popular swap (same bolt pattern as Wilwood), a master cylinder adaptor is available from Mopar Performance and other Mopar vendors which will allow the Wilwood cylinder to bolt up without drilling. Another consideration is the need for a manual brake master cylinder pushrod, since the power brake pushrod arrangement will not match with a manual brake conversion. We found the Wilwood master's piston comes without the machining for pushrod retention, so it is imperative that a positive pedal stop is incorporated.
There is preliminary bench...
There is preliminary bench assembly required to prep the Wilwood brakes for installation, including assembling the aluminum hub adaptors to the rotors, packing the wheel bearings, and mounting the hubs to the rotor assembly.
All of the critical fasteners...
All of the critical fasteners used in the Wilwood brake system call for safety wire. The required equipment here is a variety of pliers, stainless safety wire, and the know-how required to install it properly. In order to keep the fasteners secure, the wire should tension in an orientation that holds the bolts in a torqued (clockwise) direction.
Here we have a hub and rotor...
Here we have a hub and rotor assembly completed, safety wired, and ready for installation, with the second unit awaiting final assembly.
Wilwood's Mopar B- and E-body...
Wilwood's Mopar B- and E-body front disc brake kit is designed to mount to a factory drum brake spindle, whereas our Satellite came equipped with 11-inch factory discs. To use the kit on a disc brake car, the front spindles must be change to the drum brake type.
We had this '70 Challenger...
We had this '70 Challenger out back with factory drum brakes and the required spindles. The drum brake spindles are not particularly difficult to find, covering '62-72 B-body, and '70-74 E-body applications.
Replacing the spindles requires...
Replacing the spindles requires supporting the lower control arm with a jackstand to take the suspension load, then disconnecting the upper ball joint and unbolting the lower ball joint/steering arm. Here we have the drum brake spindle installed.
At this stage of the project, we installed the front conversion, master cylinder, and proportioning valve, while retaining the rear drum brakes. The rear disc conversion requires aftermarket "green" non-adjustable rear axle shaft bearings with snap-ring retention, and is not compatible with the factory tapered roller bearings. Since future plans call for a narrowed custom rear housing, it would be money down the drain to re-bearing our current axle shafts. The rear brake assembly will be included in the rear end build when we make the swap. Wilwood's proportioning valve allowed us to adjust the bias to accommodate the drums in the rear, and we can later dial in the braking system for the discs out back with a simple twist of the valve.
|WHERE THE MONEY WENT |
|PART NO.: ||DESCRIPTION: ||PRICE:* |
|140-10740-D ||Front kit, 12.19 rotor, drilled ||$1,167.95 |
|260-8555B ||Master cylinder, 1-inch, black ||$239.95 |
|220-7699 ||Flexline kit, universal, 16-inch. ||$59.95 |
|290-2210 ||Brake fluid, (6) 12-ounce bottles ||$47.95 |
|260-8419 ||Compact proportioning valve ||$41.95 |
|Misc ||Brake line ||$9.95 |
|Total: ||$1,567.70 |
|*Prices as listed from Summit Racing Equipment |
The caliper mount bolts to...
The caliper mount bolts to the spindle with new fasteners (included in the kit). The front lower ball joint bolt from the drum car is required, as it is longer than the disc brake bolt, and it is reused in the conversion.
With the rotor assemblies...
With the rotor assemblies already bench-assembled, the installation was simply a matter of sliding the hubs onto the spindles, and adjusting the wheel bearings as normal. The Wilwood hubs feature nice, machined-aluminum, screw-on spindle caps, as compared to the stamped-steel hammer-on stockers. Our kit uses Wilwood's "Dynapro 6" six-piston calipers.
The calipers must be centered...
The calipers must be centered over the rotors, with shims used at the mounting lugs to set the alignment. Add shims as required to center the caliper, and then Locktite and torque the caliper fasteners. Next, apply safety wire per the Wilwood specifications.
The brake pads are inserted...
The brake pads are inserted from the top of the caliper, and retained with a quick-release clip. Finish the installation by plumbing the brake lines. We went with Wilwood's universal 16-inch braided steel brake line kit, which fit our Satellite perfectly, and mated to the stock hard-line connection.
We weighed all of the components...
We weighed all of the components involved in the conversion and were surprised to find a savings of 19.5 pounds per side with the larger diameter 12.19-inch Wilwood brakes, a hefty savings in comparison to the OEM 11-inch discs. Along with the master cylinder conversion and eliminating the booster, we saved a total of 53.5 pounds.
To allow adjustment of the...
To allow adjustment of the brake bias front to rear, we added a Wilwood proportioning valve, and plumbed it into the line to the rear brakes. We fabbed a simple bracket to mount the valve to the inner rocker panel, which put the control knob inside the passenger compartment through an existing body plug in the floor pan.
With the proportioning valve...
With the proportioning valve location through the left-rear floor pan plug, the brake bias can be adjusted from the driver seat. We found the knob on the proportioning valve fit the existing body hole perfectly.
With the relatively light...
With the relatively light weight of our Satellite and the 12.19-inch rotors and six-piston calipers, we decided that a manual brake system would offer improved feel, less clutter, and a weight reduction. The factory iron master cylinder and brake booster were removed as an assembly.
To install the Wilwood 1-inch...
To install the Wilwood 1-inch piston master cylinder, we used a firewall reinforcement plate from a factory drum brake car. The Wilwood master uses two mounting bolts in contrast to the factory four-bolt flange. Although an adaptor is available, we re-drilled the reinforcement plate, firewall, and inner pedal bracket to the Wilwood pattern and mounted the master cylinder directly. A manual brake master cylinder pushrod is required. A positive pedal stop is also required, since the Wilwood master cylinder piston lacks the provision for the OEM-style internal pushrod retention bushing.