Lull 6K Service Manual - Manual (Page 216)

Supply, Pressure, and Return Hydraulics
5-72 Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K
1. Follow preparation procedures as outlined in Section 3 of this manual.
Be sure to follow the guidelines in this section detailed under “General
Hydraulic Maintenance Practices” on page 5-4.
2. Install brake pressure diagnostic port test gauge into brake diagnostic
port (see page 5-90).
3. While watching test gauge, press brake pedal numerous times until
pressure gauge reads 0 psi. Remove test gauge from diagnostic port.
4. Thoroughly clean hydraulic control manifold block.
5. Disconnect intermediate wiring harness (Item 1) from low brake
pressure switch.
6. Tag and slowly loosen eighteen (18) hydraulic hoses (Items 2 through
19) and bleed any remaining oil into appropriate container. Disconnect
hoses. Cap fittings and hoses.
7. Tag and slowly loosen both ends of the hydraulic tube (Item 20); bleed
any remaining oil into appropriate container. Disconnect the tube from
both O-ring connectors — the one on the hydraulic control manifold
block and the one that is attached to the boom control valve (Item 22).
Remove the hydraulic tube.
8. Take note of how fittings are attached to control manifold block. To
make sure that they are reassembled in the same position, make
sketches of those that are adjustable.
9. Remove three (3) each capscrews (Item 23), lockwashers (Item 24),
and flatwashers (Item 25) holding manifold block to valve plate
(Item 21).
10. Remove the control manifold block from the machine and take it, along
with the hydraulic tube, to a clean area appropriate for further
disassembly, cleaning, and overhauling.
Overhaul
Hydraulic Control
Manifold
Inspection and Cleaning, Hydraulic Control Manifold Block Fittings
(Ref. Fig. 5-44) The following procedure describes removal and cleaning
of the fittings used on the hydraulic control manifold.
1. Inspect and clean hydraulic tube using solvent.
2. Remove low brake pressure switch (Item 1) by loosening hex closest to
port. Do not attempt to loosen by applying tool to body of switch or
large hex (if equipped).
3. Remove all fittings (Items 2 through 18).
4. Clean fittings and threaded end of low brake pressure switch using an
solvent. Dry with compressed air.