33. When the driver depresses the _______________ pedal, the pushrod pushes the piston forward. As it moves forward, the piston pushes the cup past the vent port. As soon as the vent _______________ is covered, fluid is trapped ahead of the cup. The fluid, which is under _______________, goes through the outlet lines to the wheel brake units to apply the brakes. When the driver releases the brake pedal, the return _______________ forces the piston back to its released position. As the _______________ moves back, it pulls away from the fluid faster than the fluid can flow back from the brake lines to the pressure _______________. This creates a low pressure ahead of the piston