Blade control valve relief valve damaged or incorrectly
A restriction in the one of the leveling blade system lines
Problem: Blade position drifts when control lever is in
Blade control valve body and spool are worn.
Blade control valve centering spring is damaged.
Seal leakage in the blade cylinder.
Leveling Blade System
Blade Control Valve.
(1) Blade control valve. (2) Pressure line. (3) Nut. (4) Inlet port.
(5) Relief Valve.
Remove the side panel from the right side of the
Disconnect pressure line (2) from inlet port (4) of blade
control valve (1). Install a tee and the 0 to 25000 kPa
(0 to 3600 psi) pressure gauge from the fittings group in
inlet port (4). Connect line (2) to the tee. This gauge
will measure the blade control valve relief valve
Start and run the engine at 2200 rpm.
Pull the blade control lever back to the RAISE position.
Keep the blade control lever in the RAISE position after
the blade is completely raised. Read the pressure on
the gauge. The relief valve pressure should be
10 330 ± 345 kPa (1500 ± 50 psi).
If the relief valve pressure is not correct, it must be
adjusted. Stop the engine.
Remove nut (3) from relief valve (5). Loosen the
locknut, and turn the adjustment screw clockwise to
increase the pressure setting or counterclockwise to
decrease the pressure setting.
Check the relief valve pressure setting again. If it is
correct, tighten the locknut and install nut (3).
Remove the pressure gauge and tee from inlet port (4)
and pressure line (2). Reconnect pressure line (2) to
inlet port (4). Install the side panel.