The brake pedal uses leverage to transfer the effort from the driver’s foot to the master cylinder.
Different lever designs can alter the effort the driver needs to make, by using different levels of mechanical advantage. Brake pedals should be mounted securely, free from any excessive sideways movement, and at a height and angle that will allow the driver to quickly move from pressing the accelerator, or gas pedal, to applying the brakes.
The pedal is usually suspended from a bracket between the dash panel and the firewall, and works as a force-multiplying lever. If the power assist fails, the pedal's leverage is designed to allow the driver to still generate thousands of pounds of pressure at each wheel cylinder.
Brake pedals must be free to return to their starting position when pressure is removed. This allows the master cylinder pushrod to return to its un-depressed position.
Changes to how far the pedal can travel or to its resistance – if it feels harder or softer than normal – can be an indicator of problems such as low fluid levels or even a leak in the hydraulic system. When ABS brakes are activated during heavy braking, the pulsations of the system can be felt by the driver through the pedal and this is normal, however, a pulsating feel during normal or light braking can also be an indicator of a potential braking system problem.
