JLG 1100S Service Manual - Manual (Page 272)

SECTION 5 - HYDRAULICS
5-50 – JLG Lift – 3121256
5.7 DRIVE & FUNCTION PUMP START UP
PROCEDURES
Start-Up Procedure
The machine utilizes a Triple Combination Pump coupled
to the Deutz diesel engine. The pumps are connected in-
line to each other as follows:
1. The front hydrostatic transmission pump, or drive
pump, is coupled directly to the diesel engine and
provides oil flow to operate the machine's right side
wheels.
2. The middle hydrostatic transmission pump, or drive
pump, is coupled to the back of the front pump and
provides oil flow to operate the machine's left side
wheels.
3. The third or rear pump is the function pump. It is
coupled to the back of the middle pump and pro-
vides oil flow to operate the boom, axle, steer and
platform functions.
The transmission pumps share some common connec-
tions. Each pumps charge oil suction ports are connected
by steel tubing, the charge pumps discharge oil flows are
connected and flow to a common charge pump inline oil
filter, cleaned & filtered oil flows back to the transmission
pumps "G" ports. The pumps case drain ports are con-
nected (T1 & T2), oil flow from the middle pumps T1 port
also provides flows to the oil cooler. The charge pumps oil
pressure is regulated by a single boost oil pressure relief
valve installed in the middle pump. The front pump has an
orifice cartridge (0.047" diameter) installed in place of a
charge oil pressure relief cartridge. This insures that only
one valve controls charge pressure & provides an amount
of charge oil flow to the front pump's case to insure flush-
ing & removal of hot oil.
Each pump has its own separate electrical proportional
directional control valve to control oil flow and direction.
The signals or command values to each pump are similar
except when steering. During steering and propel of the
machine the pump supplying oil to the "inside turning
radius" has a command less than the pump supplying oil
flow to the "outside turning radius" pump.
"Posi-Traction" control, front to rear on a given side of the
machine, is accomplished by a flow divider/combiner car-
tridge installed in the Traction Control Manifold. There is a
flow divider/combiner for each side. Each flow divider/
combiner also has a "bleed orifice" to limit the amount of
flow splitting or combining.
The middle transmission pump also supplies oil to a hot
oil flushing valve cartridge, #120, in the Traction Control
Manifold. This cartridge provides a means to obtain brake
release oil pressure. The brake release pressure is con-
trolled by a pressure relief valve cartridge # 130 and a
solenoid operated brake release directional control car-
tridge, #170, also located in the Traction Control Manifold.
This is important to note as the brake release oil pressure
must be set 25 psi (1.7 bar) below the boost oil pressure
relief valve. If the brake release pressure is set too low,
brake drag and pump control will be affected. If set too
high, damage to the wheel drive parking brakes could
result. Prior to start, connect appropriate pressure gauges
to the unit.
FOR THE START-UP OF NEW OR OVERHAULED
INSTALLATIONS:
1. Insure all electrical checks have been performed &
the machine is set up correctly with the JLG Ana-
lyzer.
2. Insure the machine has all four wheels jacked &
blocked off the ground per JLG procedures.
3. Insure the triple pump assembly is installed and
connected correctly per the hydraulic circuit dia-
gram.
4. Disconnect the electrical connector from the diesel's
throttle actuator, to prevent engine start.
5. Crank the engine until charge pressure reaches 50
psi or more.
6. Re-connect throttle actuator electrical connector and
start engine. Allow engine to run at idle speed only
for at least 5 minutes. This will allow the hydrostatic
system to filled.
7. Listen for any abnormal noises.
8. Check for oil leaks.
9. Check charge pressure (500 psi +50psi, - 0 psi
[34.4 bar +3.4 bar, - 0 bar]). Pressure can be mea-
sured a pump ports Ma & Mb or by "teeing" into the
inlet for the charge oil filter. Charge pressure is
checked with the joystick in neutral. A 0-1000 psi (0-
70 bar) pressure gauge must be used. (If pressure
gauges were installed in Ma & Mb to check charge
pressure, disconnect the gauges installed in Ma &
Mb, as they will be damaged if loop pressure rises
above 1000 psi [34.4 bar].)