The lead-acid battery is the core of the electrical system, providing current to the ignition system to start the engine as well as delivering supplemental current when the alternator can't handle high electrical system loads and acting as an electrical reservoir for excessive current.

Brakes utlize friction to slow vehicle tires. Drum brakes employ a cast iron drum that roates with the vehicle axle. When hydraulic pressure is applied to the brake assemblies at the wheels, internal pistons expand and push brake shoes outward into contact with the brake drum slowing the rotation of the axle. More powerful disc brakes operate by pinching a rotating disc betweeen two brake pads and allow for a larger surface area to contact the disc, provide more force, and are more easily cooled.

Control arms (upper and lower) connect a vehicle's suspension to the frame. The connection to the wheels is through ball joints which allow the control arms to turn and move up and down simultaneously. The frame connection uses bushings.

The fuel injector sprays fuel into the air stream that's being fed into the cylinder head via the intake valve. The timing and amount of fuel are regulated by the powertrain control module (PCM) which is the main computer that controls engine and transmission functions.

During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center.