BENCH TEST PROCEDURE
(First Series)

1. After overhauling, the Hydrovac should be thoroughly tested. This can be accomplished as follows:

2. Connect hydraulic lines and vacuum line and gauges as shown in Fig 27. Open hydraulic shut off valves “A”, “B” and “C”. Close hydraulic valve “D” and vacuum valve “E”. Have Hydrovac bleeder valves 1, 2 and 8 closed.

3. Run master cylinder pressure screw “F’’ all the way out. Move master cylinder lever “G” through eight or ten complete strokes. This should completely displace the volume in the Lines and Hydrovac slave cylinder. Close shut-off valve “C” and open bleeder valve “1”. Pump the lever “G” until fluid appears at the bleeder valve, then close it. This eliminates the air in the Hydrovac jumper line.

Low Pressure Leakage Test

4. Be sure vacuum shut-off valve “E” is closed and that vacuum gauges “H” and “J” read zero. Open hydraulic shut-off valves “D”, “M” and “N”. Turn pressure screw “F” down until hydraulic gauges “K” and “L” indicate eight to ten pounds. Hold in this position for several seconds. There should be no drop in hydraulic pressure.

High Pressure Leakage Test

5. Now close valves “M” and “N”. See that vacuum gauges “H” and “J” read zero. Turn crew “F” down until hydraulic gauges “P” and “0” read 2000 pounds. Hold in this position for several seconds. There should he no drop in hydraulic pressure in this length of time. Back off screw “F” to full release position.

NOTE: If the master cylinder should travel to the end of its stroke before 2000 pound pressure can be raised, bleed all four hydraulic gauges at the valve just under the gauge. Also bleed screws two and three of the Hydrovac.

Page <21>