CAUSE
PROBLEM
REMEDY
1. Replace spring.
1. Boom base spool centering
8. Boom drops when working
spring broken.
bucket lever with boom lever
in neutral or raise position
2. Remove all foreign material
2. Boom base spool binding.
and contamination. Replace
any damaged parts.
3. Clean or install new parts
3. Holes in the restrictor poppet
or boom base spool plugged
as necessary.
4. Clean or replace as necessary.
4. External check valve on
boom section pilot pressure
cap plugged.
1. Free any binding linkage.
1. Pilot valve spools not
9. Boom drops or bucket dumps
Check for damaged spool or
positioned properly.
when loaded with control
detent balls and replace as
levers in neutral position.
necessary.
2. Adjust relief cartridge.
2. Overload relief valves set
too low or stuck open.
3. Replace spring.
3. Spool centering spring
broken.
4. Remove all foreign material
4. Spool in the main control
and contamination. Replace
valve binding.
any damaged parts.
1. Install new cylinder
1. Leakage by the cylinder
10. Boom or bucket drifts
packings.
packings.
with the engine shut off.
2. Check spools and bores for
2. Excessive leakage in valves.
excessive wear or scoring.
3. Adjust relief cartridge.
3. Overload relief valves set
too low or stuck open.
1. Adjust to proper relief
1. Faulty main relief valve.
11. Hydraulic oil is overheating.
pressure settings or replace
relief valve assembly.
2. Install new cylinder packings.
2. Leakage by the cylinder
packings.
3. Install new pump.
3. Faulty pump.
4. Install new parts as necessary.
4. Excessive leakage in either
the main control valve or
pilot valve.
5. Clean or replace cooler as
5. Cooler in the steering system
necessary.
malfunctioning.
6. Clean or replace valve as
6. Steering by-pass valve
necessary.
malfunctioning.
[ 27 ]