JLG G6-42P Service Manual - Manual (Page 500)

OPEN CENTER HYDRAULIC BRAKE VALVE
PRIMARY CUP DESIGN
(Refer to Figure 10)
Remove boot (item 1) and
pressure regulating spring
assembly (item 2).
CAUTION: Pressure regulating
spring assembly has
been set at the fac-
tory and should
never be disas-
sembled, re-adjusted
or interchanged with
another valve.
Separate end cap (item 21) from
housing (item 11).
CAUTION: Care must be taken
as end cap is under
tension of spring
(item 19).
Remove gasket (item 14).
Remove primary cup (item 17),
retainer (item 18), spring (item 19)
and residual valve (item 20) from
end cap (item 21).
Remove cap screw (item 13)
from under side of housing (item
11). Remove o-ring (item 12)
from cap screw.
Remove retaining ring (item 8)
from housing (item 11).
Remove sleeve (item 10) by
pulling on push rod (item 4).
Remove cup (item 9) from
sleeve.
Remove piston (item 16) from
housing (item 11). Remove piston
ring (item 15) from piston.
Remove retaining ring (item 3)
carefully with a small flat tool. Do
not scratch bore of sleeve (item
10).
Remove push rod (item 4), spool
(item 6) and spring (item 7) from
sleeve (item 10). Remove cup
(item 5) from spool (item 6).
Inspection
Clean and inspect all component
parts for scratches, cracks or wear.
Replace any par ts that are
excessively worn or damaged.
CAUTION: If spool (item 6), sleeve
Disassembly
1.
2.
3.
4.
5.
6.
7.
8.
9.
(item 10) or bore of
housing (item 11)
are in any way dam-
aged, scratched or
broken, the entire
assembly must be
replaced. These
parts are select-fitted
and are not inter-
changeable or re-
placeable with ser-
vice items.
Install new cup (item 9) on sleeve
(item 10) and new cup (item 5) on
spool (item 6).
CAUTION:
Assembly
Lips on cups (items
5 & 9) should be
away from ends of
spool (item 6) and
sleeve (item 10).
Place spring (item 7) in sleeve
(item 10).
Install spool (item 6) in sleeve
(item 10). Note direction of spool.
Install push rod (item 4) in sleeve
(item 10) and secure it with new
retaining ring (item 3).
Install new o-ring (item 12) on cap
screw (item 13) and install in
housing (item 11).
Carefully install sleeve (item 10)
into housing (item 11).
CAUTION: Make sure that
groove on sleeve
will engage cap
screw (item 13).
Install retaining ring (item 8).
Install new piston ring (item 15)
on piston (item 16) and install in
housing (item 11).
Place new residual valve (item
20), spring (item 19) and retainer
(item 18) in end cap (item 21).
CAUTION: Residual valve must
be checked for
proper seating in
end cap.
Place new gasket (item 14) on
mounting face of end cap (item
21) and new primary cup (item 17)
on end of spring (item 19).
Assemble end cap (item 21) with
its components to housing (item
11) making sure lip on primary
cup (item 17) has properly
engaged bore of housing.
Install lock washer (items 22) and
bolts (items 23). Torque 16 to 18
ft. lbs.
Install pressure regulating spring
assembly (item 2) on push rod
(item 4). Install new boot (item 1).
SEE BLEEDING SECTION FOR
COMPLETE BLEEDING
INSTRUCTIONS
PARTS LIST
ITEM DESCRIPTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
BOOT
PRESSURE REGULATING
SPRING ASSEMBLY
RETAINING RING
PUSH ROD
CUP
SPOOL
SPRING
RETAINING RING
CUP
SLEEVE
HOUSING
O-RING
CAP SCREW
GASKET
PISTON RING
PISTON
PRIMARY CUP
RETAINER
SPRING
RESIDUAL VALVE
END CAP
LOCKWASHERS
BOLTS •
•
•
•
•
•
•
•
•
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
(8)