Mega MMP4, Maintenance Manual

Page: 17 / 96

MMP4-CAT(T4)-MX-2
26 Feb 2014
SECTION 4
Basic Hydraulics System
4-4
4. If the hydraulic oil pressure is not within the
specifications, adjust the pressure regulator
cartridge as follows:
a. To increase the pressure, loosen the lock nut
on the regulator stem and screw in the stem
clockwise (CW) until the pressure is at 2,800
psi (19,300 kpa), tighten lock nut on stem.
b. To reduce the pressure, loosen the lock nut on
the regulator stem and unscrew the stem
counter clockwise (CCW) until the proper
pressure is obtained, tighten lock nut on
stem.
c. Recheck hydraulic pressure.
d. Shut unit off.
e. Remove pressure gauge from test port.
Hydraulic Cylinder Speed Control Valve
1. If the hydraulic boom cylinders raise too slowly or
lower too fast, check the adjustment as follows;
a. Remove protective cap.
b. Loosen jam nut.
c. Fully seat the flow control on the hydraulic
control valve for the cylinder with the travel
speed that needs adjustment.
d. Rotate knob 1/2 turn CCW.
e. Raise boom, check speed to ensure speed is
desired, if speed is too fast turn knob CW 1/
16
th
of a turn at a time, if the speed is too slow
turn knob CCW 1/16
th
of a turn at a time until
desired speed is achieved (8 seconds to full
rise).
f. Tighten jamb nut.
g. Reinstall cap.
HYDRAULIC CYLINDERS
The 2 hydraulic cylinders are used for lifting the inlet
and discharge booms to either the 'stow/travel'
position or to the 'fill' position. When the boom
control switch is operated in the 'UP' position, the
pressurized oil retracts the cylinder and lifts the
boom. The speed of the lifting and lowering is
controlled by metering valves built into the hydraulic
control valve. There are safety chains at each cylinder
to prevent any unwanted movement in the boom
when it is filled with water and as a safety precaution
in case the control valve lever is operated
accidentally. The cylinder operates in the boom
down mode by activating the control valve in the
'DOWN' position, the weight of the boom makes the
cylinder extend, lowering the boom, the built in
metering valve controls the lowering speed of the
boom.
Torque 24-26 ft-lbs flow
control for “discharge pipe”.
Set flow for 8 sec. rise.
Torque 24-26 ft-lbs flow
control for “pump pipe”.
Set flow for 8 sec. rise.
Retract.
‘Pump Pipe’
Test Port. ‘System Pipe’