When To Use Them
Using the emergency brake outside of a complete brake failure is not recommended. Doing so can damage your emergency brake, rendering it useless in times of a true emergency. Likewise, driving your vehicle with the parking brake engaged can also cause numerous damages to the emergency brake cable, service brake, brake shoes, and even rotors.
Not Using Your E-Break Can Cause Them To Fail
As odd as this may sound, it is also simple to understand. Although the emergency brake cable is housed in a protected sleeve, infrequent use can result in a build-up of corrosion. As a result, the cable becomes weak over time. As the cable becomes weaker, it is more prone to breaking when put under the stress of a real emergency situation. Normal use prevents this build-up and keeps the cable in good condition.
How To Use Them
If you are ever in the situation where your hydraulic brakes fail and you must use the emergency brake, be sure to use it properly. If the brake is pulled too quickly, it will cause the brakes to lock up quickly and the car will fishtail or skid, thus removing your removing your control over the vehicle. If you do have to use the emergency brake, be sure to pull it up slowly and steadily. This will bring the car to a safe and controlled stop.
Remember to use safe roadside practices in the event of a roadside emergency. Occasional check-ups on your car's emergency brake can help prevent or notify you of any wear and tear it might have.