Prevents brakes from locking by pulsating the pressure when you apply firmly so they don't grab.
The friction caused by the brakes causes the car to decelerate. This negative acceleration, in turn, causes a force to be applied to all those in the car. This is the lurch you feel.
They are equipped with a "telltale" warning that shrieks when the brakes are applied, with the brake pads are too low and need replacing.
They are warm because the friction makes the molecules in the brakes move faster, which causes it to warm up.
because the alignment is off Warped or out of round brake rotors/drums.
apply your brakes gently while accelerating at the same time
Check the brake fluid reservoir, it may be low on brake fluid indicating it is time to have the brakes inspected.
One possiblity could be the power brake booster is shot. When you apply the brakes it creates a large vacuum leak, enough to stall engine.
Worn bushes or warped brake rotor. Replace faulty item.
Either warped rotors or drums can cause pulsating. Apply the parking brake slowly while going about 15mph and see if t pulsates. If it does, it is the drums that need turning. If not, it is the rotors that need turning.
Time for new brakes or adjustment.
Air pressure within the air braking system of a tractor-trailer (or large truck) is what prevents the brakes from being applied. The pressure of the air pushes back a large spring at each wheel. The large spring will apply the brakes when there is no pressure in the system. When the driver steps on the brake pedal, air is released out of the system and the brakes are applied. When the driver's foot comes off the brake pedal, air is quickly pumped back into the system and the brakes are released. Disconnecting the air line has the same effect on the trailer's brakes. Air is released from the system, and the brakes are applied. It is not the brakes themselves that lock. Application of the brakes causes the wheels to lock.