11
H5-991-406A
H/G-25-SD Service (Fluid End)
a...
Inlet (3 center valves)
..From.the.large.hole.at.the.bottom.
of.the.diaphragm.pocket.in.the.valve.plate,.press.down.on.
the.spring.retainer.(16).until.the.valve.seat,.valve,.and.spring.
fall.out.of.the.bore.
.
Press.and.tap.down.as.required,.working.your.way.around.
the.edge.of.the.spacer.to.force.the.shell.subassembly,.crush.
seal,.and.spacer.evenly.out.of.the.valve.bore.
b...
Outlet (3 outer valves)
..From.the.small.hole.at.the.bottom.
of.the.diaphragm.pocket.in.the.valve.plate,.and.through.the.
valve.seat.bore,.press.down.evenly.on.the.valve.(13).until.it.
stops.against.the.spring.retainer.
.
Continue.pressing.or.tapping,.as.required,.until.the.spacer,.
crush.seal,.shell.subassembly,.spring,.and.valve.fall.out.of.
the.valve.bore.
.
Press.and.tap.down.as.required,.working.your.way.around.
the.edge.of.the.seat.holder.to.force.the.spacer.and.seat.
subassembly.evenly.out.of.the.valve.bore.
c... Inspect. both. sides. of. the. valve. plate. for. wear,. including.
the.diaphragm.pockets,.valve.bores,.and.shoulders.at.the.
bottom. of. each. bore.. Also. inspect. the. face. of. the. valve.
plate.(adjacent.to.the.valve.bores).for.wear,.especially.in.the.
areas.where.the.O-rings.seal.between.it.and.the.manifold..
Using.a.straightedge,.inspect.both.sides.of.the.valve.plate.
for.warpage..If.there.is.warpage.or.excessive.wear,.replace.
the.valve.plate.
Inspect the Valve Components
Inspect.the.individual.components.of.each.valve.as.follows:
a...Check.the.spring.retainer.(16).that.is.housed.inside.the.shell.
(45)..Be.sure.to.locate.the.polyurethane.washer.(17).that.sits.
in.the.spring.retainer.recess.and.supports.the.spring.(14)..If.
the.spring.retainer.is.worn.in.the.area.of.the.four.tabs.that.
guide.and.act.as.a.stop.for.the.valve,.replace.it.
.
Also.look.for.wear.in.the.area.of.the.recess.that.supports.
the.spring..The.polyurethane.washer.should.have.minimized.
or.prevented.wear.in.this.area.if.it.stayed.in.place.during.
operation.
.
Press.out.the.old.spring.retainer.and.push.in.a.new.one.if.
required..It.is.always.a.good.idea.to.use.a.new.polyurethane.
washer.in.the.spring.retainer.recess..Be.careful.to.put.only.
one.washer.into.each.retainer.recess.
b...Check.the.valve.spring.(14).for.wear.or.damage..Compare.
its.free.length.to.that.of.a.new.spring..A.worn.or.otherwise.
damaged.spring.should.be.replaced.with.a.new.one..Never.
attempt.to.stretch.an.old.spring.and.reuse.it.
c... Check.the.valve.(13).for.uneven.or.excessive.wear..If.it.has.
developed.an.uneven.wear.pattern.or.is.worn.excessively,.
do.not.reuse.it.—.replace.it.with.a.new.one..A.valve.with.an.
uneven.wear.pattern.will.not.seal.effectively,.even.against.
a. new. seat,. resulting. in. rough. operation. and. reduced.
output.
.
Note: Your pump has a urethane washer (44) in the
recess on the back side of each valve. It is there to
reduce or eliminate wear on the valve caused by motion
between the spring and valve. It also helps minimize
wear on the end of the spring. It is always a good idea
to replace these washers with new ones. Be careful to
put only one washer into each valve recess.
d...Remove.the.valve.seat.(3).from.its.holder.(1)..Inspect.both.
parts.for.wear.and.replace.either.or.both.as.necessary..It.is.
always.a.good.idea.to.use.a.new.valve.seat.and.O-ring.(11).
in.the.valve.seat.holder.
.
Note: Whenever you replace a worn valve, valve seat, or
valve spring in any valve assembly, we recommend that
you replace them in all valve assemblies at that time,
to ensure the most reliable operation when you restart
the pump. We also recommend that you always replace
the washers and seals in the valve assemblies at that
time, for the most reliable operation. All the necessary
parts are included in a replacement valve kit and in a
complete fluid-end kit.
