An ABS controls wheel lock-up by ( 1 ) A 3 unit force is exerted on a master cylinder. What force is exerted on the salve cylinder if its area is 4 times that of the master cylinder? ( 2 ) 0 简单液压制动(盘式).swf Brake fluid in an antilock braking system should be changed at regular intervals because ( 3 ) Rear wheel lock-up during heavy braking is controlled in ABS by ( 4 )