Lull 944E-42 Service Manual User Manual download pdf (Page 305)

8.53

Model 644E-42/944E-42 Rev. 6/04

Hydraulic System

Engine Information

Idle . . . . . . . . . . . . . . . . . . . . . . .950 ±50 rpm

Full Speed . . . . . . . . . . . . . . 2,650 ±100 rpm

Hydraulic Oil Information

Oil Type - 10W, meet ISO Grade 46

Capacity - Reservoir. . . . . 33.5 gal. (127 liter)

Capacity - System . . . . . . 50.2 gal. (190 liter)

Note: To adjust relief settings, pressure reducing

settings or standby pressure, turn the

adjustment screw clockwise to increase

pressure or counterclockwise to decrease

pressure.

The hydraulic oil temperature for the pump flow

test should be between 100-120° F (38-49° C)

(tank hot to the touch) during testing.

Equipment Needed to Perform Tests

from Hydraulic Diagnostic Test Kit

Test Location Gauge Fittings

4,000 psi gauge

(280 bar gauge)

Unit equipped with fittings from

factory.

1,000 psi gauge

(70 bar gauge)

Unit equipped with fittings from

factory.

300 psi gauge

(21 bar gauge)

Requires a #4 o-ring Boss Fitting

with Diagnostic Nipple.

2 56

4 7 83

9 10

CAUTION: GAUGE DAMAGE may occur. Malfunctioning hydraulic system

circuits may have excessive pressure and can cause hydraulic pressure spikes.

Test circuit with the highest reading pressure gauge first. If this gauge cannot

record an accurate pressure reading, use the next lower pressure gauge.

TEST

SEQUENCE

TEST

LOCATION

Hydraulic Pump Flow Test

To check flow readings, a flow meter capable of measuring 60 gpm (227,1 liter/min) and a load valve

capable of 6,000 psi (413,4 bar) will be required (not included with Hydraulic Diagnostic Test Kit).

Test both pump sections of the tandem gear pump separately. Test the primary pump section first. When testing

the pump sections, return the oil from the flow meter directly into the hydraulic tank fill hole.

Run test at 2,000 psi (137,8 bar) load @ Engine Speed of 2,500 ±25 rpm.

PRIMARY PUMP (pump section closest to the transmission) - Label and disconnect the outlet hose from the

primary pump and allow the hose to hang loose. Cover, cap or plug the primary pump outlet hose to prevent

contamination of the hydraulic system. Connect the flow meter to the outlet port on the primary pump — Flow rate

should be 16.5-19.5 GPM (62,5-73,8 liter/min).

SECONDARY PUMP (pump section furthest from the transmission) - Label and disconnect the outlet hose

from the secondary pump and connect to the outlet port on the primary pump. Connect the flow meter to the outlet

port on the secondary pump — Flow rate should be 16.5-19.5 GPM (62,5-73,8 liter/min).

IMPORTANT: When testing on the secondary pump is completed make sure to disconnect the secondary pump

outlet hose from the primary pump outlet port and reconnect it to the secondary pump outlet port. Also make sure

to re-connect the primary pump outlet hose to the primary pump outlet port.

TEST

SEQUENCE

TEST

LOCATION

Valve

Port

ADJUST.

LOCATION

COMPONENT

DESCRIPTION

PRESSURE

READINGS

PRESSURE TEST PROCEDURES

—N/A

Stand By

Pressure

200 ±25 psi

(13,8 ±1,7 bar)

With engine at idle, check the pressure. The pressure is not

adjustable. If the pressure is incorrect, replace unloader

cartridge on Main Control Valve.

PPG

Pilot Valve

Pressure

500-600 psi

(34,5-41,4 bar)

With engine at idle, check the pressure. If the pressure is

incorrect, adjust or replace the pressure reducing cartridge

located on the accumulator charge/secondary function valve.

PBG

Accumulator

Charge/

Secondary

Function Valve

Park Brake

Release

500-600 psi

(34,5-41,4 bar)

With engine at idle, turn the park brake switch to the disengaged

position. Check the pressure. If the pressure is incorrect, adjust

or replace the pressure reducing cartridge located on the

accumulator charge/secondary function valve.

Power Steering

Supply

2,400-2,600 psi

(165-179 bar)

With engine at idle, turn the steering wheel all the way in one

direction and hold while checking pressure. If pressure is

incorrect, adjust or replace the relief valve located on the

accumulator charge/secondary function valve.

SW N/A

Accumulator

Charge/

Secondary

Function Valve

See “Pressure

Test Procedures”

for Pressure

Readings

At start up, the pressure should jump up to and stop

momentarily at 450 psi (31 bar), which is the pre-charge

pressure. The pressure should then continue to rise to 1,900-

2,100 psi (131-145 bar) which is the accumulator charge

pressure. Let the system bleed down naturally with the engine

at idle (minimum of 2 minutes). The accumulator charge

pressure should recharge at 1050 ±50 psi (72 ±3,4 bar).

—

Main System

Relief

3,400-3,600 psi

(234-248 bar)

With engine at high idle, use the boom control lever to fully

retract the boom. Hold over relief and check pressure. If

pressure is incorrect, adjust or replace cartridge located in the

end section of the main control valve.

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Lull 944E-42 Service Manual User Manual Page 305

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Lull 944E-42 Service Manual User Manual Page 305

Comments to this Manuals

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