REMEDY
CAUSE
PROBLEM
4. Remove all foreign material
4. Low pressure relief poppet
3. (Continued)
and contamination. Replace
stuck closed.
any damaged parts.
5. Clean or replace parts as
5. Flow restricted in the lines
necessary.
between the main valve and
pilot valve, or in the external
check valve on the boom
section pilot pressure cap.
6. Clean or replace the lines as
6. Flow restricted in the pilot
necessary.
valve return line.
7. Clean or replace the lines
7. Flow restricted in the main
control return line.
as necessary.
1. Remove all foreign material
1. Boom spools in main control
4. Boom powers down slowly.
and contamination. Replace
valve binding.
any damaged parts.
2. Clean or install new parts
2. Holes in restrictor poppets
as necessary.
or main valve spools
plugged.
3. Repair or replace as
3. Flow restricted through the
necessary.
external check valve on the
boom section pilot pressure
cap.
1. Remove all foreign material
1. Main flow control poppet
5. System chatters when
and contamination. Replace
and relief valve assembly
powering down boom.
any damaged parts.
stuck open.
2. Check the return spring.
2. Low pressure relief poppet
Remove all burrs, foreign
stuck open.
material, and contamination
from bore, poppet, and seat.
Be sure poppet moves freely
and seats properly.
3. Clean bore and check. Replace
3. Anti-void check stuck closed.
any damaged parts.
4. Repair or replace.
4. External check valve on the
boom section pilot pressure
cap malfunctioning.
5. Clean or install new parts
5. Holes in restrictor poppets
as necessary.
or main valve spools plugged
See causes and remedies listed under Item No. 2. NOTE: Inspection
6. Bucket will not roll back or
of parts must be made in the bucket section of the main control valve
rolls back slowly.
and pilot valve instead of the boom sections.
7. Bucket does not dump
See causes and remedies listed under Item Nos. 4 and 5. NOTE: Inspection of
parts must be made in the bucket sections of the main control valve and pilot
properly.
valve instead of the boom sections.
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