JLG G6-42A Service Manual - Manual (Page 70)

Boom
3-32 G6-42A, G9-43A, G10-43A
7. If access is required, loosen and remove any clamps
securing the lift/lower cylinder (1 & 2) and extend/
retract cylinder tubes (3 & 4) to the frame.
8. Disconnect the extend/retract cylinder tubes from
the extend/retract cylinder hoses (3 & 4). Install caps
or plugs in tubes to prevent fluid loss and to keep dirt
and debris from entering the hydraulic system.
9. Using the hoses and fittings specified, connect the
hoses between the auxiliary hydraulic power supply
and the extend/retract hoses of the affected
machine. Retract hose (3) is the supply and extend
hose (4) is the return. Connect the hoses in the
proper order to ensure that the cylinder is retracted,
not extended.
10. Remove the previously installed boom support.
11. Use the auxiliary power supply to slowly retract the
extend/retract cylinder.
12. Properly support the boom as required.
13. Loosen and remove the jumper hoses, caps, plugs
and reconnect the extend/retract cylinder hoses.
Torque as required.
b. Lower the boom as follows:
1. Place a suitable receptacle under the tube/hose
connections.
2. Disconnect the lift/lower cylinder hoses from the lift/
lower cylinder tubes (1 & 2). Install caps or plugs in
tubes to prevent fluid loss and to keep dirt and debris
from entering the hydraulic system.
3. Using the hoses and fittings specified, connect the
hoses between the auxiliary hydraulic power supply
and the lift/lower hoses of the affected machine. Lift
hose (1) is the return and lower hose (2) is the
supply. Connect the hoses in the proper order to
ensure that the boom is lowered, not raised.
4. Remove the previously installed boom support.
5. Use the auxiliary power supply to slowly lower the
boom.
6. Loosen and remove the jumper hoses, caps, plugs
and reconnect the lift/lower cylinder hoses.
7. Install the previously remove clamps securing the lift/
lower cylinder and the extend/retract tubes. Torque
as required.
8. Install the plastic cover over the main control valve.
9. Transfer any hydraulic oil into a suitable, covered
container, and label the container as “Used Oil.”
Dispose of used oil at an approved recycling facility.
10. Clean up all debris, hydraulic oil, etc., in, on, near
and around the machine.
11. Remove the Do Not Operate Tag on both the ignition
key switch and steering wheel.
MY8630
MY8620
G6-42A
1
4
G9-43A
G10-43A
3 2
4
2
3
1