Gravely 950001, Maintenance Manual

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2. Back off the adjusting screw lock nut and use an
Allen wrench for adjustment (see below).
3. With the engine running at normal operating speed
and all valves in the “Neutral” position, the
pressure gauge should be reading 350 psi. (24
bar). If the pressure setting requires adjustment,
turn the adjusting screw clockwise to increase
pressure or counterclockwise to reduce pressure.
When the setting is correct, tighten the lock nut and
re-check the pressure gauge reading to be correct.
7.12 QUICK DISCONNECT COUPLINGS
The only maintenance on the male and female
coupling halves is replacement.
Replacement of the Quick Disconnect coupling is
carried out with the system shut down.
Disconnection is achieved by retracting the spring
loaded outer sleeve of the female coupling to release
the locking balls. The male half will then be ejected by
the force of the two spring loaded poppet valves inside
the coupling halves that oppose each other. As the
coupling halves separate, the poppet valve in each half
snaps shut to close off and seal the lines on the
implement and the machine.
Connection of the two coupling halves is achieved by
retracting the outer sleeve of the female coupling. Then
firmly pushing the male half into the female half, this
pushes the locking balls outwards and unseats both
poppet valves. Releasing the outer sleeve holds the
locking balls captive in the groove of the male half
coupling locking both halves securely together.
Dust Caps And Plugs
It is essential that coupling dust caps and plugs are
replaced when couplings are disconnected to prevent
grit and contaminates entering the hydraulic system.
Failure to do this could cause system malfunctions and
will shorten the life of hydraulic components.
CAUTION: This over center valve pressure
setting is important to machine operational
safety. It prevents the machine from
overrunning when driving down hill.
Lock Nut
Adjusting Screw
SECTIONAL DRAWING OF OVERCENTRE VALVE
Sectional Drawing of Overcenter Valve