SECTION 4, Page 31SJKB-40-D, SJKB-40-D/F JUN. 1999
TROUBLESHOOTING (Cont.)
TROUBLE PROBABLE CAUSE REMEDY
HYDRAULIC SYSTEM (Cont.)
NO PLATFORM LEVEL-
ING UP
1. Stuck or defective platform level
up valve 4H-41A.
2. Leveling master cylinder by
passing internally.
3. Stuck counter balance valve
CB13.
1. Clean Valve. Replace if defective.
2. Rebuild cylinder. Replace if
damaged.
3. Clean Valve. Replace if defective.
NO PLATFORM LEVEL-
ING UP OR DOWN
1. Plugged orifice.
PLATFORM DRIFTS
DOWN
1. Clean Orifice.
1. Leaking or defective counter
balance valve CB12.
1. Check Valve. Replace if
defective.
PLATFORM WILL NOT
STAY LEVEL WITH
BOOM MOTION
1. Leveling master cylinder by
passing internally.
2. Leaking or defective counter
balance valve CB12(down) or
CB13(up).
1. Rebuild cylinder. Replace if
damaged.
2. Check Valve. Replace if
defective.
BRAKES WILL NOT RE-
LEASE
1. Defective brake valve 3H-26A.
2. Defective or misadjusted pressure
reducing valve PR1.
3. Defective relief valve RV8.
4. Stuck shuttle valve SV1.
1. Check Valve. Replace if
defective.
2. Check Valve. Replace if
defective.
3. Check Valve. Replace if
defective.
4. Check Valve. Replace if
defective.
BRAKES WILL NOT EN-
GAGE
1. Stuck or defective brake valve 3H-
26A.
2. Brakes out of adjustment.
3. Brake apply control valve FC2
closed.
1. Check Valve. Replace if
defective.
2. Refer to section 5 for adjustment
procedure.
3. Refer to section 5 for adjustment
procedure.
NO DRIVE FORWARD
OR REVERSE
1. Brakes will not release.
2. Defective relief valve RV5.
3. Defective pressure over-ride valve
P.O.R.1.
4. Defective or stuck directional
valve 4H-15 or 4H-16.
5. Defective main drive pump P1.
6. Defective drive motor M1.
1. Refer to section 5, "brake
diagnostics".
2. Refer to section 5 for test
procedure. Replace if defective.
3. Refer to section 5 for test
procedure. Replace if defective.
4. Check Valve. Replace if
defective.
5. Refer to section 5, "drive pump
diagnostics.
6. Refer to section 5, "drive motor
test procedures". Replace if
defective.
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