Continuing To Pursue Problem Brakes On 1996 3500 2wd With Rear Antilock Brakes Only. Now Believe Problem Is In Antilock Valve, What Is Best Method To Test Valve As Replacement Is $1200 Plus. Symptoms Are That After Bleeding Wheel Cylinders Brake Pedal Is Solid With Engine Off But Sinks When Engine Running. Is There A Special Bleeding Technique For This Valve?