L8-6 Hoist Circuit Component Repair L08031
6. Remove plug (4, Figure 8-10) from end of spool
(7). Remove spring seat (2) and spring (3).
Remove poppet (5) and spool end (6).
NOTE: Pay special attention to poppets (5, 10 and
25, Figure 8-10) during removal to ensure proper
location during reassembly. Poppets may be
identified with a colored dot; red, white or green. If
poppets are not color coded, use the following chart
for identification:
7. Repeat step 6 for the opposite end of spool (7)
and the top end of spool (23).
8. Remove spool end (22), spring retainer (20) and
spring (21).
9. Remove cover (16), remove O-rings (18 & 19).
Cleaning and Inspection
1. Discard all O-rings and backup rings. Clean all
parts in solvent and blow dry with compressed
air.
2. Inspect all springs for breaks or distortion.
Inspect poppet seating surfaces for nicks or
excessive wear. All seats must be sharp and
free of nicks.
3. Inspect all bores and surfaces of sliding parts for
nicks, scores or excessive wear.
4. Inspect all poppets in their respective bore for fit.
Poppets should move freely without binding
through a complete revolution.
Assembly
1. Lubricate O-rings (18 & 19, Figure 8-10), with
clean hydraulic oil. Install O-rings in spool
housing and install cover (16). Secure cover in
place with capscrews. Tighten capscrews to 60
ft. lbs. (81 N.m) torque.
2. Install spring (3, Figure 8-10) in spool (7). Install
spring seat (2). Apply Loctite
®
to the threads of
spool end (6). Install spool end (6) and tighten
to 25 ft. lbs. (34 N.m) torque. Install poppet (5).
Apply Dri-loc #204 to the threads of plug (4).
Install plug (4) and tighten to 15 ft. lbs. (20
N.m) torque.
NOTE: Poppets 5, 10 and 25 may be color coded
and must be installed in their original location.
3. Repeat step 2 for the opposite end of spool (7).
Make sure spring (8) is blue in color.
4. Lubricate spool assembly (7) and carefully
install in spool housing (15). Make sure the “V”
groove in spool (7) is in the up position, or
toward cover (1).
5. Repeat step 2 for the top end of spool (23). The
bottom end of spool (23) does not contain a
poppet or plug. Install spring (21) which is blue
in color, spring seat (20) and spool end (22).
Apply Loctite to spool end threads. Install spool
end (22) and tighten to 25 ft. lbs. (34 N.m)
torque.
6. Lubricate the assembled spool (23) and install in
spool housing (15). Make sure the “V” groove is
in the up position, or toward cover (1).
NOTE: Spools (7) and (23) are physically
interchangeable. Make sure spool (23) is installed
toward the base port of the spool housing.
7. Install new O-ring and backup ring on restrictor
poppet (1, Figure 8-8). Install restrictor poppet
in housing.
8. Install new O-rings (12 & 13, Figure 8-10).
9. Install new O-ring and backup ring on poppet (1,
Figure 8-7). Make sure the small steel ball is
installed in poppet (1). Install poppet (1) in
cover (3).
10. Install covers (1, Figure 8-10). Secure cover in
place with capscrews. Tighten capscrews to 60
ft. lbs. (81 N.m) torque.
POPPET
COLOR
ORIFICE DIAMETER
DRILL
SIZE
White 0.063 in. (1.6 mm) #52
Green 0.093 in. (2.4 mm) #42
Red 0.110 in. (2.8 mm) #35
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