4-47. Single Over Center Valve.
This task covers:
General Mechanics Automotive Tool Kit
Bay removed (para. 2-16).
(Item 1, Appendix B)
Hydraulic Test Equipment
Teflon tape (Item 19, Appendix E)
a. Test. (figure 4-56)
Single over center valve removed for test. See para. c. below.
Connect a 0-6,000 psi (0-41,307 kpa) pressure source and gage to cylinder relief pressure port.
Connect a 0-300psi(0-2,068 kpa) pressure source and a 0-500 psi (0-3,448 kpa) gage to pilot pressure port.
Connect hydraulic fluid reservoir and 0-30 gpm (0-144 Lpm) to valve port.
Set pilot port pressure to 0 psi (0 kpa).
Apply pressure to cylinder relief pressure port and record the pressure at which flow occurs between cylinder
relief pressure and port valve port.
Increase pilot pressure, port pressure in 50 psi (345 kpa) increments and record pressure at which flow oc-
curs between cylinder relief pressure port and valve port.
Increase pilot pressure port pressure up to 250 psi (1 ,705 kpa) or until pressure at which flow between cylin-
der relief pressure port and cylinder port is 0 psi (0 kpa).
Adjust single over center valve, see para. b. below, if performance is not within tolerances.
Reduce all pressure to 0 psi (0 kpa) and disconnect connectors.
FOLLOW-ON MAINTENANCE: Install single over center valve (para. c.).