Daewoo Solar 300LC-V, Manual

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S0709401K
Page 41
Main Control Valve (Kayaba)
RELIEF VALVE
HYDRAULIC SYSTEM
ADJUSTMENT OF RELIEF VALVE
Main Relief Valve
1. Connect an accurate pressure gauge to inlet port.
2. Start engine and maintain rated pump speed.
3. Shift control valve spool and read pressure gauge from stroke end of cylinder.
NOTE: Shift a spool that the actuator pressure setting of the over load relief valve is higher than
the pressure of the main relief valve.
4. High pressure adjustment (1st stage) (refer to figure of page 32/63)
A. Loosen lock nut (7) and tighten plug (8) until piston contacts step (* mark) of plug (6). Plug (8)
should be torqued below 19.6 N*M. While plug (8) is tightened, plug (6) should not be turned.
Distance A (Page 32/63) must be more than 4.0 mm (0.16 in). Tighten lock nut (7).
Problem Possible Cause Remedy
Pressure does not rise. Stuck main poppet, sleeve or pilot
poppet opened or dirt in seat part. Replace relief valve.
Relief pressure unstable Seat parts of pilot poppet damaged.
Piston or main poppet stuck.
Relief pressure is
incorrect. Seat parts worn due to dust.
Lock nut and adjuster loose. Reset pressure and tighten lock
nut in rated torque.
Oil leaks Relief valve seat parts damaged Replace relief valve.
Every parts stuck due to dust
O-ring worn. Replace adjuster or O-ring.
Problem Possible Cause Remedy
Hydraulic system is
malfunction or does not
operate. Hydraulic pump failed. Check pressure or replace pump.
Relief valve failed. Replace pump.
Some kinds of cylinders failed. Repair or replace.
Pump load pressure too high. Check circuit pressure.
Valve cracked. Replace valve assembly.
Spool does not fully stroke. Check spool operation.
Hydraulic oil level in tank too low. Add hydraulic oil.
Filter in circuit plugged. Clean or replace filter.
Circuit piping twisted. Check piping.