The parking brake, also known as the emergency brake or handbrake, is an important safety feature in vehicles. As the name suggests, it’s intended to keep a parked vehicle stationary, particularly on slopes. However, many drivers have wondered – how far can you actually drive with the parking brake on before you cause damage?
What is the Parking Brake For?
The parking brake works independently of the hydraulic brake system. In most modern vehicles, it engages the rear brakes only, though some older vehicle models may also actuate the front brakes.
The parking brake uses a mechanical cable and lever system. Pulling up on the lever manually engages the brake shoes against the drum or caliper against the rotor. This holds the rear wheels locked in position when the vehicle is parked.
Using the parking brake properly means fully disengaging it before attempting to drive. The parking brake is not designed to be used for stopping or slowing a moving vehicle. The hydraulic foot brake is the proper brake to use while driving.
Dangers of Driving with the Parking Brake On
While it is technically possible to drive a short distance with the parking brake partially engaged, it puts significant strain on the braking system. The faster you drive and the tighter the parking brake is engaged, the more damage can occur.
Potential dangers and damage from driving with the parking brake on include:
- Excessive wear on brake pads/shoes – The parking brake uses the same rear brake pads or shoes as the hydraulic system. Dragging these components at speed generates a lot of friction and heat, wearing them out prematurely.
- Overheating brakes – Too much heat from brake drag can boil brake fluid, warp or crack brake rotors, and cause the brakes to fade. Complete brake failure can result.
- Damaged cables/linkages – The parking brake cables are not designed to withstand high loads or be constantly under tension. Driving with the parking brake engaged can over-stress and stretch the cables.
- Flat spots on tires – If the parking brake is tight enough to lock the rear wheels, it can cause flat spots on the tires as they skid along the pavement. This makes for a bumpy ride.
- Transmission wear – For manual transmissions, driving with the parking brake on forces the clutch to slip excessively, prematurely wearing out the clutch plate.
- Reduced control – Having the parking brake on compromises normal braking capability. It also makes the vehicle harder to steer and control, especially in slippery conditions.
How Far Can You Drive Like This?
There is no set distance that is safe to drive with the parking brake partially on before risking damage. It depends on several factors:
- Parking brake tension – A loosely engaged parking brake that is just starting to contact the pads or shoes will not cause as much damage as one that is ratcheted up tight.
- Vehicle speed – The faster you drive, the quicker damage can occur from overheating and excessive friction. Even low speeds generate damaging heat surprisingly quickly.
- Brake condition – Brakes already worn down will overheat faster than brakes with plenty of pad/shoe material remaining. Old, compromised brakes suffer the most.
- Brake type – Drum brakes typically handle brake drag better and take longer to severely overheat compared to disc brakes. But neither is designed for this kind of use.
- Drive duration – The longer you drive with the parking brake engaged, even lightly, the greater the likelihood of damage occurring.
Under the worst conditions – high speeds, tightly engaged brake, compromised brakes – severe damage can occur within a mile or less. Even low speeds can damage brakes in just a few miles if the parking brake is really snug.
The only truly safe answer is not to drive with the parking brake on at all. If you feel or hear the parking brake drag at all while driving, pull over and release it immediately.
Signs of Parking Brake Drag
How can you tell if you’ve been driving with the parking brake partially engaged? Signs include:
- Burning smell from the brakes
- Brake squeal or scraping noises
- Reduced brake pedal pressure
- Excessive heat around the wheels
- Brake vibration or pulling to one side
- Flattened rear tires
Any of these warn you that components are being overworked. Pull over and inspect the brakes. Don’t continue driving or you risk further damage.
Consequences of Driving Too Far
What can happen if you ignore the signs and drive too far with the parking brake applied? Potential consequences include:
- Severely worn brake pads/shoes, requiring premature replacement
- Brake fluid boiling over or leaking
- Warped or cracked brake rotors
- Melted brake components if overheated severely
- Damaged brake cables needing repair
- Rear tire damage from skidding
- Complete brake failure, putting you in danger
The repair costs magnify the longer you drive like this. A short drive may just require new pads. But warped rotors, leaked fluid, and damaged cables could cost hundreds more if repairs are extensive.
Proper Parking Brake Use
Using your parking properly is easy. Follow these steps:
- Bring the vehicle to a complete stop.
- Hold the brake pedal down firmly.
- Pull the parking brake lever up slowly. Listen for the ratcheting sound.
- Release the regular brake pedal to allow the parking brake to hold the vehicle.
- Before driving, press and hold the brake pedal down.
- Push the parking brake lever down fully to release.
Only use the parking brake when stopped and parked. Never while actively driving or for slowing a moving vehicle. If you have trouble releasing a stubborn parking brake, get it fixed right away.
When to Use the Parking Brake
Besides parking on steep hills, common times to set the parking brake include:
- Parking at curbs – Engaging the parking brake reduces the chance of rolling into traffic if bumped or nudged.
- Extended parking – For long-term parking like at work or the airport, use the parking brake to take stress off the transmission.
- Parked in gear – When parked in gear for a manual transmission, also set the parking brake as a backup.
- During vehicle maintenance – Engage the parking brake when you have the vehicle up on jacks to prevent any movement.
- Waiting in traffic – Some drivers use the parking brake in stop-and-go traffic to give their foot a rest.
Signs of Parking Brake Problems
If your parking brake isn’t working properly, signs can include:
- Lever raises up without resistance
- Has to be pulled up too far to engage
- Clicking or grinding noises during use
- Brake warning light on the dash
- Cannot get the vehicle to hold still when parked
Any parking brake problems should be addressed immediately before further driving the vehicle. The parking brake is considered a safety-critical system.
While the parking brake has its name for a reason, it should never be used when the vehicle is in motion. Driving any significant distance with it even partially engaged can generate damaging heat and friction.
Listen and watch for the signs of parking brake drag. If you suspect it is not fully disengaged, pull over right away before the brake system can be compromised. Using your parking brake properly and fixing problems early ensures it works safely when you really need it.