Electronic Parking Brake Cures Hot Rodder's Headaches

Wilwood recently brought parking brakes for hot rodders into the 21st-century with our Electronic Parking Brake (EPB) Caliper, which can be adapted to almost anything. Many modern cars use electronic, motor-driven, disc brake calipers for parking. Our R & D team studied these and began work on our own proprietary controller and stand alone caliper. 

Now your car can easily add the safety and security of a parking brake, without ruining the look!

Parking Brakes for Discs Were Problematic

From the early days of four-wheel disc brake installation, the parking brake question has caused headaches. Of course, race cars don't need them, but street-driven projects and factory-equipped vehicles certainly did. The standard solution was to include a second drum brake on the rear, hidden inside the disc. While this worked well, it added many extra parts to the braking system, not to mention unsprung weight to the axle.

Because it works so well, Wilwood also engineered many rear disc brake kits with this same system. We make big brake kits that work with your factory internal parking brake parts, plus our own mini internal drum brake design for disc retrofit kits.

There was a good reason for resorting to an auxiliary drum brake for parking use - drum brake systems require less clamping force to be effective. When applying the brakes with a cable and lever, it is hard to produce enough clamping force on disc brake pads to provide adequate braking. On top of that, drum brakes are self-exciting, meaning if the car does roll, the brake shoes are pressed harder into the drum, stopping it.

The engineers in Detroit, and elsewhere, were working on a simpler solution almost since the dawn of disc brakes. Cadillac, and other manufacturers, had disc calipers with a cable and screw set up by the 1970s - the cable pulls a lever, rotating a screw, and the screw presses the pad against the rotor. The screw provided much more clamping force than a cam or lever alone, but the cable pull length limited screw rotation. The limited travel meant proper adjustment was crucial to keeping them working well as the pads wore and cables stretched.

Over the years, Wilwood created a better hydraulic/mechanical hybrid rear caliper. The current Combination P-Brake Caliper is available for 1994-2014 Ford Mustang, vehicles using Ford 9-inch rear differentials, and many front-wheel-drive cars. This caliper offered a simple solution to builders, but still requires routing cables and finding a place for a parking brake lever inside the cockpit.

Electronically Activated Parking Brakes

Electronic parking brake systems first appeared on high-end German luxury cars about 20 years ago. Some of these systems were just electric motors, which pulled a cable, but the more advanced ones integrate an electric motor and screw into the rear caliper. Push a button, and the brakes lock with as much force as stepping on the pedal would have.

Now Wilwood has introduced a standalone Electronic Parking Brake (EPB) caliper that is simple to mount almost anywhere. Wilwood created a small standalone controller and dedicated switch along with the caliper, making installation easy on almost any car or truck. All parts are available separately or together in a retrofit kit.

When activated, the electric motor causes the caliper to clamp the rotor with 2400lbs of force yet draws no power from the battery until you hit the switch again to deactivate it. That is more clamping force than your leg applies in everyday driving. The EPB and controller automatically adjust to wear in the rotors and pads and applies the same amount of pressure regardless. 

Because Wilwood mounting brackets for rear calipers feature bolt holes around the entire perimeter, the brake and EPB calipers can be positioned in a dozen different places around the axle. No matter what sort of rear suspension your car has, you should be able to fit the EPB and brake caliper. And because all it needs are two wires to function, there is no need to worry about routing the cables and running them straight to the handle or pedal in the passenger compartment.

Wilwood EPB Kits

Wilwood has already started integrating this advanced system into its popular high-performance brake kits. Because the Ford 9-inch is so widely used, we began with kits for those in quite a few different variations. Chevy/GM 10 and 12-bolt differential kits are also available for popular muscle cars. It is even an OEM part for armored Toyota Land Cruiser (J70) conversions popular in Africa, Australia, and the Middle East. We will also sell just the calipers and controller, or a retrofit kit with the EPB parts to adapt to whatever discs you are using.

The Wilwood EPB caliper comes in a left or right-hand configuration, based on which side the electric motor is on. But because there are no hydraulics involved, if clearance dictates using one on the "wrong" side, it's not an issue. These calipers come in three different models, for .81", 1.10" or 1.25" wide rotors, and work on rotors from 11" to 14" in diameter.

The Electronic Advantage

There are advantages to an electric parking brake system, even if you are the type who likes to keep things as simple as possible. Automakers moved toward them in new cars because of the advantages in packaging and functionality. Many hobbyists have been scrounging electronic parking brake parts from various junked vehicles because of how neatly they solve the issue of keeping your car from rolling when parked.

Activating the parking brake with a switch and a few wires simplifies things under the car, at the rear wheels, and in the cockpit. The Wilwood momentary-on switch has a red LED glow around it once activated, but can be easily wired to any indicator light, including the factory warning. Because the switch is so easy to package, it can be installed under the dash, in the glove box, in the center console, or anywhere, to prevent the car from being stolen or easily towed away. Plus you get the simple peace of mind of knowing your vehicle isn't going to roll into traffic.

Cable activated parking brake systems are surprisingly tricky to package because the cables only work within a narrow-angle of pull at the wheels. If you have ever looked under an old car, it is not unusual to see a system with levers, pulleys, brackets, and cables running along the frame and to the firewall. With just a few very flexible wires, an EPB caliper is as easy to hook up as a brake light.

 

The ease of routing wires solves other problems as well. No longer will your frame, cross members, driveshaft, exhaust, and parking brake cables fight for space under your car. You can easily route your wires right alongside your brake hard and flex lines, through the tightest spaces. Vehicles with multilink independent rear suspension can be especially tricky to route brake cables on and it looks a mess too. If you have a truck with lots of articulation, or an extreme lift, an electronic parking brake may be the only way to fit a proper parking brake without worrying about cables binding or snagging.

Wilwood is even happy to sell you just the EPB caliper and let you design the switch and controller. What you can do is limited only by your ability to imagine and build an electronic controller for it. What can you do with the Wilwood EPB?