JLG Skytrak 6036 Service Manual page 179

Section 9. Hydraulic System
19. Thread four studs (3), washers (2) nuts (1) into
shaft end cover (16) and tighten alternately or
cross corner. Rotate the drive shaft with a 6
inch wrench to make certain there is no
binding in the pump. After the fasteners are
tight and you are sure there is no internal
binding, torque the diagonally opposite
fasteners to 200 lb-ft (271,2 N m).
h. Installation
1. Place a new gasket (15, Fig. 9.37) and main
tandem pump (14) in position on the transmis-
sion and secure using two hex head
capscrews (12) and lock washers (13).
Torque capscrews to 75 lb-ft (101,7 N m).
2. Fill the pump inlet port and outlet ports with
hydraulic oil to provide initial lubrication
3. Install elbow (11) and connector (10) to the
pump outlets.
4. Install small pump outlet hose assembly (8)
and large pump outlet hose assembly (9).
5. Install O-ring (7) in elbow (5). Position clamp
halves (6) and elbow (5) on pump inlet and
secure with four lock washers (4), and four
hex head capscrews (3). Torque capscrews
to 75 lb-ft (101,7 N m).
6. Check hose clamp (1) to be sure it is secure.
i. Recommended Test Procedure
Perform pump testing in accordance with proce-
dures in SAE Handbooks. Refer to Hydraulic
Pump Test Procedure SAE J745c.
1. Be sure to run the pump in the clockwise
direction (from the drive end). Driving the
pump in the wrong direction will build up
pressure behind the shaft seal, damaging it
and requiring replacement.
2. Be sure there is an adequate supply of oil for
the pump, at least one gallon of oil for each
gpm of pump capacity.
3. If one section of the tandem pump is being
tested, make sure that the other section which
is not being tested is adequately supplied with
oil. If any of the sections run dry, or if plugs
are left in ports, serious and permanent
damage will result.
4. Use a good quality Grade 46 hydraulic oil
rated at 215 SSU at 100 °F ±5 °F (38 °C ± 3 °
C). Refer to Specifications in this section.
5. The feed line must be of adequate size with no
more than 5" mercury vacuum adjacent to the
pump inlet. As a rule, the feed line must
Model 6036 S/N 9B0499 and Before
provide a feed flow velocity not in excess of 8
feet per second.
6. Run the pump at least two minutes at no load
and moderate speed (not below 400 or over
1500 rpm). If the pump becomes excessively
hot, shut down immediately and locate the
problem source.
7. Gradually increase pressure on pump, in 500
psi increments until the desired test pressure
has been reached. This should take about
five minutes.
8. Average Output Specifications at 3500 psi
(241 bar)
Pump Section Speed (RPM)
30 gpm
30 gpm
30 gpm
30 gpm
15 gpm
15 gpm
15 gpm
15 gpm
j. Recommended Start-up Procedure for New
or Rebuilt Pump
After connecting the lines and mounting the
replacement unit, start-up as follows:
1. Make sure that the pump suction line is
securely clamped at the pump inlet and the
reservoir.
2. Disconnect the fuel run solenoid to prevent the
engine from starting.
3. Turn the ignition switch to START position and
crank the engine for 15 to 25 seconds. This
will prime the main tandem pump.
4. Turn the ignition switch OFF.
5. Reconnect the fuel run solenoid.
IMPORTANT : DO NOT operate any boom or
steering functions during pump test.
6. Start the engine and operate the pump at least
two minutes at no load and at a speed of over
400 rpm but below 1500 rpm. During this
break-in period, the unit should run free and
not develop and excessive amount of heat. If
the unit operates properly, speed and pres-
sure can then be increased to normal operat-
ing settings.
Output (GPM)
1000 11
1500 18
2000 24
2500 30
1000 7
1500 11
2000 15.5
2500 20
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