The parking brake is a brake system used to hold one or more brakes incessantly in applied position. The parking brake employs the usual drum brakes on the rear wheel. Instead of hydraulic pressure, however, a easy mechanical linkage is used to engage the brake shoes. When the parking-brake pedal is despondent (or, in some cars, a hand lever is raised), a steel cable pulls taut a worry lever; other cables draw the brake shoes firmly against the drums. The discharge knob slackens the cables and disengages the brake shoes. The parking brake is self adjusting. A mechanical adjuster in the piston moves on the thrust screw to compensate for lining wear.