JLG 680S, Service And Maintenance Manual

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SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS
5-40 3121234
HIGH PRESSURE RELIEF
1. Install a high pressure gauge at the “M1” port of the
main valve block.
2. Activate telescope in and hold. The gauge should read
2800 psi (179.3 bar).
3. To make an adjustment to this pressure, go back to the
engine compartment to the function pump. The high
pressure relief adjustment is the lower one of the (2) on
the compensator. To adjust this, a 4 mm and 6 mm allen
wrench will be needed. The adjustment screw is facing
the shaft end of the pump, or toward the engine.
a. First, using the 4 mm wrench, loosen the setscrew
on the side of the compensator (facing you) which is
in line with the adjustment screw. This is a jam nut
screw which holds the main adjustment from turn-
ing. Loosen it 1 turn.
b. Next, using the 6 mm wrench adjust the main
adjustment clockwise to increase or counterclock-
wise to decrease. This adjustment will be reset at the
end of this procedure to 2500 psi (172.3 bar). This is
the
maximum relief pressure for all functions gov-
erned by this pump.
Adjustments Made at the Main Control Valve Block
TELESCOPE OUT
1. Install a high pressure gauge at the “M3” port of the
main valve block.
2. Activate Telescope out. The gauge should read 2500 psi
(172.3 Bar).
3. The relief valve is located directly below the M3 port.
Turn clockwise to increase, counterclockwise to
decrease.
SWING LEFT AND RIGHT
1. Lock the turntable lock pin.
2. Install the hi-pressure gauge at M2.
3. Activate swing, the gauge should read 1700 psi
(117 Bar).
4. The adjustment cartridge is located right above the M2
port. Turn clockwise to increase, counterclockwise to
decrease.