Brake cables are used to transfer the lever action of an emergency brake pedal or lever to (usually) the rear wheels. There it will activate the parking brake hardware and engage or disengage the parking brake.
Brake cables can be come rusted or corroded over time, and potentially break when they are needed most. Other times they may just give out over the course of normal use, as can be found by drivers of manual transmissions or those who live in hilly areas. Having your brake cables, and the rest of the parking brake system, inspected on a regular basis is a good idea.
Servicing the emergency brake system will vary in difficulty based on the vehicle and its age. Always consult with an automotive service professional if you're unsure about how to perform a job.
We sell quality brake cables from these manufacturers: