Solving Automotive Parking Brake Problems
Find an answer to the question, is it a parking brake or an emergency brake? In addition, learn how these systems operate and how to diagnose and repair common problems with manually operated brakes.
Parking Brake or Emergency Brake
A lot of people wonder if the term parking brake and emergency brake are interchangeable and if they refer to the same automotive system. The short answer to this question is yes. Both terms point to the same manually operated brake system. On modern automobiles, the term parking brake seems a better fit. People with automatic transmissions seldom set the parking brake, whereas drivers of a manual transmission automobile will almost always set it so the vehicle doesn’t roll if it pops out of gear when parked.
Some folks will argue that these manually-operated brakes back up the hydraulic systems in case of catastrophic failure. Although this was true of automobiles manufactured a hundred years ago, modern cars have redundant backups built into the highly reliable hydraulics. Simply put, we use the system more often for parking than for emergencies. Nevertheless, I will flip-flop between both terms throughout this article in the interest of the fair play.
Hand Brakes or Foot Brakes
These terms relate to the manner in which we apply the parking brake. A hand brake refers to a ratcheting lever assembly that’s pulled into place with the driver’s hand. These are often found in smaller automobiles and can be located on the lower dash or integrated into the center console on vehicles with bucket seats. They incorporate a release for a lever-type hand brake in the form of a push-button built into the handle. This button connects to a rod that releases the ratcheting mechanism.
A foot brake is often associated with large passenger vehicles or pickup trucks. Located to the extreme left of the brake pedal the ratcheting mechanism is set with the drivers left foot and held in position with a pendulum lock. The release for a foot applied parking brake is usually located on the left side lower dash. When the driver pulls the release, a cable leading down to the ratcheting assembly releases the lock mechanism.
Ratcheting Park Brake Actuator Problems
Although a ratcheting emergency brake actuator, whether it’s foot-operated or hand-operated, are for the most part reliable, problems can still develop. This is especially true for high mileage vehicles with manual transmissions since they use the parking brake more often than on an automatic transmission automobile. One of the most common problems is when the ratcheting assembly refuses to hold in the applied position.
The mechanical portion of the actuator boils down to a pendulum that locks against a set of pointed metal teeth. These locking teeth can become rounded and eventually strip. This problem requires the replacement of the parking brake actuator assembly. However, it’s often possible to adjust the emergency brake cable, so the striped teeth aren’t engaged against the pendulum lock. As an example, you can tighten the cable so the lock engages after the third click instead of engaging after ten clicks, thereby avoiding the stripped teeth.
Emergency Brake Cable Problems
The emergency brake cable connects the interior ratcheting actuator to the parking brake system mounted on the rear axle. The actual brake pads or shoes that stop the vehicle from rolling can be applied by a ratcheting rear disc caliper squeezing the brake pads against a rotor. The other type of system uses emergency brake shoes that we’ll talk about in a minute.
The manual cable that applies the brakes is often a two-piece assembly. This setup turns the drivers’ application into equalized pressure on both sides of the rear axle using an equalizer bracket at the rear cable connection. Since emergency brake cables run outside of the vehicle and exposed to harsh conditions its common for the cable to develop problems associated with corrosion. When this occurs replacement is recommended as lubrication is usually ineffective or temporary at best.
Problems with Rear Drum Style E Brakes
Although the shoe and drum system is much more reliable than the ratcheting disc caliper type, it’s still possible to have issues requiring service. Often these can be self-inflicted. As an example, if a driver forgets to release the emergency brake, ignores the horrendous amount of brake noise and continues to drive, the E brake shoes will most likely need replacing. This procedure is much like replacing the rear brakes on a standard drum type system. The shoes are held down to the rear axle backing plate with spring-loaded retainers and hardware that allows them to release when the driver releases the emergency brake.