Brakes Applied

Pressing pedal moves pedal rod and spool valve. This closes fluid return to pump and admits fluid into boost chamber from pressure port. Additional valve movement restricts flow between power steering pump and power steering gear.

As fluid pressure increases in boost chamber, it forces piston forward, actuating master cylinder piston and applying brakes. If steering is required while braking, power steering pump pressure will rise and spool valve will shift open, allowing more fluid to flow to power steering gear.