im not sure exactly how much pressure but in my last car ( pug 405 ) one of the metal pipes had broke so i tried repairing it using hydraulic pipe rated to 300 psi , it was fine at tick over but as soon as i tried turning the wheels the pipe just burst . one of the diesel fitters in work reckons about 500 psi is a good guess .when you say ac pump do you mean the heater blower or the ac pump cos the ac pump only pump fluid so it wont give any volume of air out
it all depends on the size of your the master and slaves cylinders how fast it will work cos im pretty sure it will give the pressure if set up correctly cos can use large hydraulic presses that give over 20 tons of force and they are only powered buy a hand lever so a power steering pump should do it no problems of course it wont be the fastest ram in the world cos the pump wont put out a large volume . hope that helps