For this test the valve shaft must be harnessed in the midposition (1-inch plunger stroke), and the RETURN port must be plugged. Apply hydraulic pressure of 2,250 psi to the BRAKE port. There should be no evidence of external leakage, permanent distortion, failure, or malfunction of any part of the valve.

PUMPING TEST. -To perform the pumping test, you should connect a reservoir to the RETURN port by means of a 3/8-inch ID hose that is at least 24 inches long. Position the reservoir in such a way that the fluid is above (but not more than 6 inches) the RETURN port. Move the shaft to the fully actuated (2-inch plunger stroke) position, and then cap the BRAKE port.

To perform the pumping test, cycle the valve rapidly. A rapid decrease in the length of successive pressure strokes should be noted. On each cycle the return stroke should be self-motivated.

LEAKAGE TEST. Reposition the unit on the bench and harness the valve shaft in the midposition. With the RETURN and PRESSURE ports open, hydraulic pressure of 25 psi should be applied to the BRAKE port. There should be no evidence of external leakage, failure, or malfunction of any part of the valve. After the first minute, leakage at the RETURN port should not exceed 1 cubic centimeter per minute for 2 minutes. If satisfactory at this stage, repeat the procedure by using 500 psi at the BRAKE port.

With the valve in the relaxed position, apply static hydraulic pressure of 5 psi to the BRAKE and RETURN ports. There should be no external leakage, failure, or malfunction of any part of the valve. Repeat the procedure with 200 psi of static hydraulic pressure.

A pressure of 2,250 psi should be applied to the PRESSURE port with the BRAKE and RETURN ports open. Maintain the pressure for 2 minutes, and then look for evidence of external leakage, failure, or permanent set. Perform this step twice.

OUTPUT PRESSURE TEST. -This test is performed in three stages. Apply hydraulic pressure of 1,500 psi to the PRESSURE port, and apply successive plunger loads of 47 pounds, 124 pounds, and 190 pounds. As a result of these applications, the pressure output readings at the BRAKE port should be 100 to 160 pounds on the first load, 660 to 750 pounds on the second load, and 1,135 to 1,255 pounds on the third load.

LEAKAGE TEST. -The leakage test for the power section requires 1,500 psi of hydraulic pressure at the PRESSURE port with the BRAKE and RETURN ports open. With the valve shaft in the relaxed position, the combined leakage from the open ports should not exceed 25 cubic centimeters per minute for the last 4 minutes of a 5-minute period. If the unit checks out, proceed to the next step.

With 1,500 psi still applied to the PRESSURE port, plug the BRAKE port, and then extend the valve shaft to midposition. Leakage from the RETURN port should not exceed 25 cubic centimeters per minute for the last 4 minutes of a 5-minute period.

FLOW TEST. TO perform the flow test, you should apply hydraulic pressure of 1,500 psi to the PRESSURE port. Move the plunger between 3/8 and 5/8 of an inch. Minimum flow at the BRAKE port should be 2 gpm, and there should be no evidence of chatter or instability.

After testing is completed, remove the valve from the test bench, flush it with hydraulic preservative oil, drip-drain the unit, and plug all ports. The body should be rubber-stamped with the cure date of the oldest O-ring or packing and tagged with the date of the test and the results.