REMEDY
CAUSE
PROBLEM
3. Check the return springs and all
2. (a) (Continued)
3. Relief valve malfunctioning.
o-rings and back-up rings. Be
sure all poppets move freely and
seat properly. Be sure piston at
internal end of relief valve
moves freely in bore. Remove all
foreign material and
contamination. Replace parts
as necessary.
4. Clean or replace as necessary
4. Flow restricted through the
pilot supply hole in the main
flow control poppet and
relief valve assembly.
5. Check return spring. Remove
5. Anti-void poppet stuck open.
all burrs, foreign material, and
contamination from bore, seat,
and poppet. Be sure poppet
moves freely and seats properly.
6. Adjust relief cartridge.
6. Boom base overload relief
valve set too low or stuck open.
7. Install new cylinder packings
7. Leakage by cylinder packings.
8. Replace pump.
8. Defective pump.
1. Remove all foreign material
1. Load check stuck closed.
(b) High pressures
and contamination.
2. Remove all foreign material
2. Boom spools binding in
and contamination. Replace
main control valve.
any damaged parts.
3. Clean or replace the line as
3. Flow restricted in the return
necessary.
line from the main control
valve.
4. Clean or replace the line as
4. Flow restricted in the return
necessary.
line from the pilot valve.
1. Free any binding linkage. Check
1. Pilot valve spool not
3. Boom will not float down or
for damaged spool or detent
positioning properly.
floats down slowly.
balls and replace as necessary.
2. Remove all foreign material
2. Boom spools in main control
and contamination. Replace
valve binding.
any damaged parts.
3. Remove all foreign material
3. One or both of the float
and contamination. Replace
poppets in the boom section
any damaged parts.
stuck closed.
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