SkyTrak 8042 Service Manual - Manual (Page 500)

8.85 Model 8042, 10042, 10054 Legacy Rev. 10/03
Hydraulic System
Disassemble the Relief Valve (Lift/Lower and Extend/
Retract Sections)
The relief valves (3) on the lift/lower section (1) and the
extend/retract section (2) are preset at 3250 ±50 psi
(224 ±3,5 bar).
1. Remove the relief valve (3) from the appropriate
section.
2. Remove the o-ring (4) from the relief valve.
3. Grip the relief valve body (5) with a suitable tool and
use another tool to remove the nut (6), revealing an
adjustment screw (7) and an o-ring (8).
4. Remove the spring (9) and poppet (10) from the plug
(11).
5. Remove the o-ring (12), large spring (13), back-up
ring (14), o-ring (15), small spring (16), poppet (17),
o-ring (18), back-up ring (19), small poppet (20) and
large poppet (21) from the body (5).
Disassemble the Mid-Inlet/Outlet Section
1. Remove the shuttle (28) from the mid-inlet/outlet
section (22).
2. Remove the shut-off plug (23).
3. Remove the remaining plugs (24 and 26) and o-rings
(25 and 27).
d. Main Control Valve Parts Cleaning
Clean all components with a suitable cleaner, such as
triclorethylene, before continuing. Blow dry.
e. Main Control Valve Parts Inspection
Inspect all parts and internal passageways for wear,
damage, etc. If inner surfaces of any component DO NOT
display an ultra-smooth, polished finish, or are damaged
in any way, replace the damaged part. Often, dirty
hydraulic fluid causes failure of internal seals, damage to
the polished surfaces within the component, and wear of
and/or harm to other parts.