When Should You Release The Parking Brake

Releasing the parking brake might seem like a straightforward process – just pull the lever or press the button, right? Well, not always. Understanding when to release it, and perhaps more importantly, when not to, is crucial for the longevity of your brake system and overall vehicle safety. As an experienced DIYer, you know that details matter, and this is one of those details that separates a competent job from a potential headache down the road.

Understanding the Parking Brake System

Before we dive into the 'when,' let's quickly recap the 'what.' The parking brake, also known as the emergency brake (though its primary function is parking, not emergencies), is a secondary braking system designed to hold the vehicle stationary, particularly on inclines. It operates independently of your hydraulic service brakes (the ones you use when driving). Most parking brake systems fall into a few categories:

Cable-Operated: The most common type. A cable connects the parking brake lever or pedal to the rear brakes. Pulling the lever tightens the cable, actuating the brakes. These brakes may be drum-in-hat or mechanically actuated disc brake calipers.
Electric Parking Brake (EPB): Increasingly common in newer vehicles. An electric motor engages the brakes, often through a button or switch in the cabin. EPBs usually integrate with other vehicle systems like hill hold assist. These typically actuate the standard disc brake calipers through electric motors.
Drum Brakes (Specific Parking Brake System): Older vehicles, and some modern ones still utilizing a rear drum brake system will simply use the drum brake shoes for the parking brake actuation via a cable.

Regardless of the type, the key principle remains the same: to mechanically restrain the vehicle's wheels from turning.

The Golden Rule: Level Ground and No Load

The most obvious and universally applicable rule for releasing the parking brake is to do so only when the vehicle is on level ground and is not under any significant load (i.e., not being pulled by another vehicle or experiencing significant wind resistance). This minimizes the stress on the parking brake mechanism and prevents potential damage or premature wear.

Think of it like this: the parking brake is designed to hold a stationary vehicle, not to stop a moving one. Releasing it under load forces the mechanism to work harder, accelerating wear on the pads, shoes, cables, or the EPB motor. On a significant slope, the car's weight will lurch against the released parking brake, causing a sudden release that can strain the system and potentially lead to a runaway vehicle if the service brakes aren't immediately engaged.

Releasing After Being Parked on an Incline

Okay, so what if you have been parked on an incline? This is where finesse and a bit of anticipation come into play. Here's the recommended procedure:

Ensure the Engine is Running: This provides power for your service brakes.
Engage the Service Brakes Firmly: Press and hold the brake pedal firmly. This is your primary line of defense.
Shift into Drive (for automatics) or First Gear (for manuals): This will create a slight opposing force. For a downhill parking position, reverse gear should be selected.
Gradually Release the Parking Brake: Do this slowly and smoothly. As you release the parking brake, be prepared to modulate the service brake pedal to maintain control of the vehicle's movement.
Check for Movement: As you fully release the parking brake, observe the vehicle for any unexpected movement. If the car starts to roll, immediately re-engage the service brakes and reassess the situation.

The goal is to transfer the holding force smoothly from the parking brake to the service brakes, minimizing any sudden jolts or stress on either system. With practice, this becomes second nature.

When Cold Temperatures Become a Factor

Cold weather presents a unique challenge, especially for cable-operated parking brakes. Moisture can accumulate in the cable housing and freeze, effectively binding the cable. In such cases, releasing the parking brake can be difficult, or even impossible, without causing damage. Never attempt to force the release.

What to do:

Try Rocking the Vehicle: Gently rock the vehicle back and forth to see if you can break the ice bond.
Warm the Brake System: If safe to do so, use a heat gun or hair dryer to gently warm the area around the cable housing and brake components. Never use open flames.
Professional Assistance: If the cable remains frozen, consult a professional mechanic. Forcing the issue can snap the cable, requiring costly repairs.

Prevention is key here. Regularly inspect your parking brake cables for any signs of damage or corrosion and lubricate them as needed (check your vehicle's service manual for recommended lubricants).

Electric Parking Brake Considerations

EPBs are generally more resistant to freezing because the actuation is controlled electronically. However, they are not immune to problems. A low battery or a faulty sensor can prevent the EPB from releasing properly. Many EPBs have a manual override function, often hidden behind a panel or accessible through the vehicle's infotainment system. Consult your owner's manual to locate and understand how to use the manual override.

Important Note: If your EPB fails to release automatically, do not attempt to drive the vehicle. Doing so can damage the EPB motor and braking components. Seek professional assistance.

The 'Never Emerge From The Vehicle' Rule

This is an extremely important safety reminder and is applicable to both auto and manual drivers: Never release the parking brake if you, the driver, are getting out of the car on an incline! Doing so could very easily lead to a dangerous roll-away situation where you are no longer in control. Always put your vehicle in park, apply the parking brake, and then turn the engine off before exiting. An uncontrolled roll-away can cause serious damage and potential bodily harm, so never skip this step.

Regular Maintenance Matters

Like any mechanical system, your parking brake requires regular maintenance to ensure its proper functioning. Here are a few key checks:

Parking Brake Cable Adjustment: Over time, the parking brake cable can stretch, reducing its effectiveness. Adjust the cable tension according to your vehicle's service manual.
Brake Pad/Shoe Inspection: Inspect the parking brake pads or shoes for wear and replace them as needed. Worn pads/shoes will reduce the parking brake's holding power.
EPB System Check: For EPBs, ensure the system is functioning correctly by performing a diagnostic scan with an appropriate scan tool. Address any fault codes promptly.

By understanding the mechanics of your parking brake, following these guidelines, and performing regular maintenance, you can ensure its reliable operation and contribute to your vehicle's overall safety and longevity.