1
G5-991-400B
G/H-25 Service (Fluid End)
NOTE: The numbers in parentheses refer to the parts
illustrations.
This. section. explains. how. to. disassemble. and. inspect. all.
easily-serviceable. parts. of. the. pump.. Repair. procedures. for.
the.hydraulic.end.(oil.reservoir).of.the.pump.are.included.in.a.
later.section.of.the.manual.
CAUTION: Do not disassemble the hydraulic end unless
you are a skilled mechanic. For assistance, contact Wanner
Engineering (TEL 612-332-5681 or FAX 612-332-6937) or
the distributor in your area.
CAUTION: The four bolts (26) that screw through the back
of the housing into the cylinder casting hold the casting
over the hydraulic end of the pump. Do not remove them
except when repairing the hydraulic end.
1. Remove Manifold (7), and
Valve Plate (18)
.
a...Remove. all. bolts. (5). and. lockwashers. (6). around..
manifold. (7).. . Do. not. remove. four. bolts. (6). that. are.
installed.through.back.of.pump.housing.(30).
.
b...With. 3/8-in. (10-mm). hex. Allen. wrench,. remove....
centerbolt.(1).and.washer.().in.center.of.manifold.
.
.
CAUTION: Do not turn the pump drive shaft while
the manifold and valve plate are off the pump,
except when removing diaphragms or repriming the
hydraulic cells.
.
c... Remove. manifold. (7). and. support. plate. (43,. used. on.
non-metallic.pump.only)..
.
d...Inspect.manifold.for.warping.or.wear.around.inlet.and.
outlet.ports..If.wear.is.excessive,.replace.manifold.
.
.
To.check.for.warped.manifold,.remove.O-rings.and.place.
straightedge.across.it..If.warped.replace.
.
e...Remove.three.socket-head.cap.screws.(39).with.3/16-in..
(5-mm).hex.Allen.wrench.
.
f... Inspect. valve. plate. (18). for. warping. as. in. step. d. for.
manifold..If.warped.replace.
.
.
NOTE: Plastic valve plates and manifolds should
also be inspected for cracks, and replaced as
necessary.
2. Inspect Valve Assemblies
(parts 11-16, and 38)
.
NOTE: The three inlet and three outlet valve assemblies
in the pump are identical (but face in opposite
directions).
.
Inspect.each.valve.assembly.as.follows:
.
a...Check.spring.retainer.(16),.and.replace.if.worn.
.
b...Check. valve. spring. (14).. If. shorter. than. new. spring,.
replace..(Don’t.stretch.old.spring.)
.
c... Check.valve.poppet.(13)..If.worn,.replace.
.
.
NOTE: If pump has plastic spring retainers, there is
a tetra seal O-ring (15) between the retainer (16) and
valve seat (12).
.
d...Remove. valve. seat. (1).. (Seat. remover. is. included. in.
Wanner.Tool.Kit.).On.cast.iron.valve.plates,.be.careful.
not.to.break.metal.ridge.around.O-ring.groove.
.
.
Inspect.valve.seat.for.wear..If.worn,.replace.and.install.
new.O-ring.(11).
.
e...Reinstall.valve.assemblies:
. .
•..Clean. valve. ports. and. valve. shoulders. with. emery.
cloth,. and. grease. with. lubricating. gel. or. petroleum.
jelly.
. .
•..Install.O-ring.(11).on.valve.seat.(1).
. .
NOTE: Some pumps use plastic dampening
washers (38) between the valve seat (12) and the
manifold (7) or valve plate (18). Refer to the parts
illustrations and the fluid-end exploded views in
the Parts Manual.
. .
•.
Inlet (3 center valves)
..Insert.retainer.(16).into.valve.
plate. (18),. then. spring. (14),. valve. (13),. and. valve.........
seat.(1)..If.pump.has.
plastic
.retainers,.O-ring.(15).
goes.between.retainer.and.seat.
. .
•.
Outlet (3 outer valves)
..Insert.valve.seat.(1),.valve.
(13),.and.spring.(14),.then.retainer.(16)..If.pump.has.
plastic
. retainers,. install. the. O-ring. (15). between.
retainer.and.seat..If.pump.has.
metal
retainers.in.outlet.
valves,. position. them. so. leg. does. not. point. toward.
center.of.pump..See.illustration.following.
W0200A
