Early Bronco Emergency Brake

Early Bronco Parking Brake Components and Adjustment Guide

The 1966-77 Ford Bronco parking brake system is a simple but effective mechanical setup designed to hold the vehicle stationary when parked. While it doesn’t look complicated at first glance, it relies on several interconnected components that must work together correctly to function as intended.

The Early Bronco parking brake consists of three primary sections: the pedal assembly, the cable assembly, and the rear drum brake hardware.

1966-77 Ford Bronco Emergency Brake Pedal Assembly

There were two different emergency brake pedal assemblies used during the Early Bronco production run.

• 1966-75 Broncos used the standard pedal assembly

• 1976-77 Broncos received a beefier version with heavier construction

Despite the difference, all currently available replacement pedal assemblies on the market are patterned after the 1966-75 design. These assemblies work just fine in 1976-77 Broncos and bolt directly into place without modification.

Both versions mount to the driver-side inner kick panel, with an additional forward bolt that secures the assembly to the underside of the dash panel. The pedal is engaged by pressing down with your foot, which locks the ratcheting mechanism in place. To release the parking brake, you pull the “Brake Release” lever located just under the dash, allowing the pedal to return to its resting position.

Early Bronco E-Brake Cable Assembly

The emergency brake cable system remained mostly unchanged from 1966 through 1976, with a notable update in 1977.

• Rear brake cables are the same for all stock Early Broncos

• The front center cable and linkage changed in 1977

From 1966-76, the front center cable used a traditional cable end that connected to a pivot lever and adjustment rod. This setup transferred pedal movement to the equalizer bar, which then pulled evenly on both rear cables.

In 1977, Ford simplified the system by adding threads to the end of the front center cable. This threaded cable end bolted directly to the equalizer bar, eliminating the pivot lever and adjustment rod entirely. The result was a cleaner design with fewer moving parts and easier adjustment.

Because of this change, 1977 Broncos require year-specific front cables, while earlier Broncos use the traditional linkage setup.

66-77 Bronco Rear Drum Emergency Brake Hardware

Inside the rear brake drums is where the parking brake actually does its work.

The drum assembly includes emergency brake link bars and spreader bars that mechanically force the brake shoes outward when the parking brake is engaged.

Here’s how it works:

When the pedal is pressed, tension is applied through the cable system to the emergency brake lever inside each drum. This lever pushes on the link bar, which in turn moves the spreader bar. The spreader bar presses the brake shoes outward against the inside of the drum, creating friction that holds the vehicle in place.

This system is completely mechanical and independent of the hydraulic braking system, which is why proper adjustment and hardware condition are critical.

There are different link bars and spreader bars depending on rear drum size:

• 10-inch rear drums

• 11-inch rear drums

Drum size is measured from the inside diameter of the brake drum, and using the wrong hardware will prevent the parking brake from working correctly.

How to Adjust the Parking Brake on an Early Bronco

Proper adjustment is key to a functional parking brake. If it’s too loose, the Bronco will roll. Too tight, and the brakes can drag.

Step 1: Adjust the Rear Brake Shoes First

Before touching the parking brake cables, make sure the rear brake shoes are properly adjusted. Adjust them until there is slight drag when spinning the rear wheels by hand.

Step 2: Inspect the Cables and Hardware

Make sure all cables move freely and that the link bars, spreader bars, and levers inside the drums are installed correctly and not seized or worn.

Step 3: Adjust the Front Center Cable

• On 1966-76 Broncos, adjust the parking brake using the adjustment rod in the linkage

• On 1977 Broncos, adjust the threaded front center cable where it mounts to the equalizer bar

Tighten the adjustment until the slack is removed from the system but the rear wheels still spin freely.

Step 4: Test Pedal Engagement

Press the parking brake pedal. It should engage firmly within a reasonable amount of travel and hold the Bronco securely. If the pedal travels too far, tighten the adjustment slightly and re-test.

Step 5: Final Check

Release the pedal and make sure the rear brakes are not dragging. Recheck adjustment after a short drive, as cables can settle.

A properly set up Early Bronco emergency brake should engage smoothly, release cleanly, and hold the truck on an incline without drama. When everything is adjusted correctly, this old-school mechanical system is simple, reliable, and effective—just like the Bronco itself.