SkyTrak 6036 Service Manual - Manual (Page 220)

Section 9 Hydraulic System
9-70 Model 6036/6036T S/N 9B0500 thru 14833
6. Unscrew adjustment screw (15) from plug
(12).
7. Invert the plug. Pilot spring (14) and pilot
poppet (13) should drop out.
8. Remove O-rings (9 and 11) and backup ring
(10) from the plug.
9. Remove piston spring (8), piston (7) and relief
valve poppet (6) from check valve poppet (3).
10. Remove and discard O-ring (5) and backup
ring (4) from the relief valve poppet.
Cleaning and Drying
Clean metal parts in an approved solvent such as
trichlorethylene and blow dry.
Inspection and Replacement
1. Inspect the poppet seating surfaces. They
must be sharp, clean, and free of nicks or
excessive wear. Replace the part if worn or
damaged.
2. Install new O-rings and backup rings. Repair
kits are available, refer to 6036 Parts Manual
for kits.
3. Clean out the channel in piston (7, Fig. 9.39)
through which fluid passes.
4. Make sure the piston moves freely in the relief
valve poppet.
Assembly
1. Lubricate with hydraulic oil and install new O-
ring (5, Fig. 9.39) and backup ring (4) on relief
valve poppet (6). Stretch O-ring, do not roll it
to fit.
2. Lubricate poppet (6) with hydraulic oil and
insert into check valve poppet (3) followed by
piston (7) and piston spring (8).
3. Lubricate with hydraulic oil and install new O-
ring (9), backup ring (10) and O-ring (11) on
plug (12). Stretch O-rings, do not roll them to
fit.
4. Lubricate exterior of plug (12) and insert into
poppet (3).
5. Insert pilot poppet (13) and poppet spring (14)
into the plug.
6. Install adjustment screw (15) into the plug.
7. Lubricate and install new O-rings (16) on nuts
(17 and 18). Stretch O-rings, do not roll them
to fit.
8. Install jam nut (17) and acorn nut (18) on the
adjustment screw. Torque nuts on relief valve
to 10 ± 1.5 lb-ft (13,5 ± 2 Nm).
9. Install the relief valve cartridge in the housing.
The cartridge is a honed fit and may require
gentle tapping to install.
IMPORTANT: Care must be taken to avoid
damaging the valve’s internal lands.
10. Lubricate and install new O-ring (1) on hous-
ing (2). Stretch O-ring, do not roll it to fit.
11. Install assembled relief valve in the control
valve housing. Torque all relief valves except
main relief valve to 40 ± 4 lb-ft (55 ± 5,5 Nm).
Torque main relief valve to 60 to 80 lb-ft (82 to
109 Nm).
12. Adjust all relief valves pressure as instructed
in paragraph 9.2.
c. Repair of Main Control Valve
Disassembly
To replace seals between the sections of the main
control valve:
1. Remove nuts (21 and 22, Fig. 9.40) at outlet
section (2).
2. Remove outlet section carefully to avoid
loosing spring (7).
3. Remove O-ring (5) and discard.
4. Remove check valve spring (7) and check
valve poppet (6) from boom extend/retract
section (4).
5. Remove boom extend/retract section (4), and
repeat steps 3 and 4 for the boom raise/lower
section (3).
6. Remove boom raise/lower section (3) and
remove O-ring (5).
6. Remove nuts (21 and 22) and tie rods (19 and
20) at inlet section (1).
Cleaning and Drying
Clean all metal parts in an approved solvent such
as trichlorethylene and blow dry.
Assembly
1. Thread nuts (21 and 22, Fig. 9.40) onto ends
of tie rods (19 and 20) until nuts are flush with
the ends of the tie rods.
2. Install new O-ring (5) in boom raise/lower
section (3).
3. Install tie rods (19 and 20) from the outside of
inlet section (1) through the holes in the inlet
section.