Graco 253485 Operation manual

Instructions – Parts List
ALUMINUM AND STAINLESS STEEL
Huskyt1590 Air-Operated
Diaphragm Pumps
120 psi (0.8 MPa, 8 bar) Maximum Fluid Working Pressure
120 psi (0.8 MPa, 8 bar) Maximum Air Input Pressure
*Model No. DB3___ Aluminum Pumps
*Model No. DC3___ Aluminum Pumps, Remote
*Model No. DB4___ Stainless Steel Pumps
*Model No. DC4___ Stainless Steel Pumps, Remote
*Model No. DBC___ Aluminum BSPT Pumps
*Model No. DCC___ Aluminum BSPT Pumps, Remote
*Model No. DBD___ Stainless Steel BSPT Pumps
*Model No. DCD___ Stainless Steel BSPT Pumps, Remote
*Model No. DT4___ Stainless Steel Plus** Pumps
*Model No. DU4___ Stainless Steel Plus** Pumps, Remote
*Model No. DTD___ Stainless Steel BSPT Plus** Pumps
*Model No. DUD___ Stainless Steel BSPT Plus** Pumps, Remote
*Model No. 253485 Aluminum Pump
*Model No. 232502 Private-Label Aluminum Pump
* Refer to the Pump Matrix and descriptions on page 22 to
determine the configuration and model number of your pump.
** Plus models include stainless steel center sections.
Patent No.
CN ZL94102643.4
FR 9408894
JA 3517270
US 5,386,452
308441AJ
Model No. DB3777 shown
03263B
Important Safety Instructions
Read all warnings and instructions in this manual.
Save these instructions.

2 308441
Table of Contents
Safety Warnings 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symbols 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service
Repairing the Air Valve 14. . . . . . . . . . . . . . . . . . . . . .
Ball Check Valve Repair 16. . . . . . . . . . . . . . . . . . . . .
Diaphragm Repair 17. . . . . . . . . . . . . . . . . . . . . . . . . .
Bearing and Air Gasket Removal 20. . . . . . . . . . . . .
Pump Matrix 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair Kit Matrix 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Torque Sequence 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dimensions 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Data 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance Chart 31. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Graco Warranties 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Graco Information 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symbols
Warning Symbol
WARNING
This symbol alerts you to the possibility of serious
injury or death if you do not follow the instructions.
Caution Symbol
CAUTION
This symbol alerts you to the possibility of damage to
or destruction of equipment if you do not follow the
instructions.
EQUIPMENT MISUSE HAZARD
Equipment misuse can cause the equipment to rupture or malfunction and result in serious injury.
This equipment is for professional use only.
Read all instruction manuals, tags, and labels before operating the equipment.
Use the equipment only for its intended purpose. If you are not sure, call your Graco distributor.
Do not alter or modify this equipment. Use only genuine Graco parts and accessories.
Check equipment daily. Repair or replace worn or damaged parts immediately.
Do not exceed the maximum working pressure of the lowest rated component in your system.
This equipment has a 120 psi (0.8 MPa, 8 bar) maximum working pressure at 120 psi (0.8
MPa, 8 bar) maximum incoming air pressure.
Use fluids and solvents which are compatible with the equipment wetted parts. Refer to the
Technical Data section of all equipment manuals. Read the fluid and solvent manufacturer’s
warnings.
Do not use 1,1,1–trichloroethane, methylene chloride, other halogenated hydrocarbon solvents or
fluids containing such solvents in pressurized aluminum equipment. Such use could result in a
chemical reaction, with the possibility of explosion.
Do not use hoses to pull equipment.
Route hoses away from traffic areas, sharp edges, moving parts, and hot surfaces. Do not ex-
pose Graco hoses to temperatures above 82C (180F) or below –40C (–40F).
Do not lift pressurized equipment.
Comply with all applicable local, state, and national fire, electrical, and safety regulations.
INSTRUCTIONS
WARNING

308441 3
TOXIC FLUID HAZARD
Hazardous fluid or toxic fumes can cause serious injury or death if splashed in the eyes or on the
skin, inhaled, or swallowed.
Know the specific hazards of the fluid you are using.
Store hazardous fluid in an approved container. Dispose of hazardous fluid according to all local,
state and national guidelines.
Always wear protective eyewear, gloves, clothing and respirator as recommended by the fluid
and solvent manufacturer.
Pipe and dispose of the exhaust air safely, away from people, animals, and food handling areas.
If the diaphragm fails, the fluid is exhausted along with the air. See Air Exhaust Ventilation on
page 8.
FIRE AND EXPLOSION HAZARD
Improper grounding, poor ventilation, open flames or sparks can cause a hazardous condition and
result in a fire or explosion and serious injury.
Ground the equipment. Refer to Grounding on page 4.
If there is any static sparking or you feel an electric shock while using this equipment, stop
pumping immediately. Do not use the equipment until you identify and correct the problem.
Provide fresh air ventilation to avoid the buildup of flammable fumes from solvents or the fluid
being sprayed.
Pipe and dispose of the exhaust air safely, away from all sources of ignition. If the diaphragm
fails, the fluid is exhausted along with the air. See Air Exhaust Ventilation on page 8.
Keep the work area free of debris, including solvent, rags, and gasoline.
Electrically disconnect all equipment in the work area.
Extinguish all open flames or pilot lights in the work area.
Do not smoke in the work area.
Do not turn on or off any light switch in the work area while operating or if fumes are present.
Do not operate a gasoline engine in the work area.
WARNING

4 308441
Installation
General Information
The typical installation shown in Fig. 2 is only a
guide for selecting and installing system compo-
nents. Contact your Graco distributor for assistance
in planning a system to suit your needs.
Always use Genuine Graco Parts and Accessories.
Refer to Product Data Sheet 305646.
Reference numbers and letters in parentheses refer
to the callouts in the figures and the parts lists on
pages 25–24.
Lift the pump by grasping the outlet manifold (1)
securely. See Fig. 3 on page 7.
TOXIC FLUID HAZARD
Hazardous fluid or toxic fumes can
cause serious injury or death if splashed
in the eyes or on the skin, inhaled, or
swallowed.
1. Read TOXIC FLUID HAZARD on page 3.
2. Use fluids and solvents which are compatible
with the equipment wetted parts. Refer to the
Technical Data section of all equipment manu-
als. Read the fluid and solvent manufacturer’s
warnings.
WARNING
Tightening Screws Before First Use
Before using the pump for the first time, check and
retorque all external fasteners. See Torque Se-
quence, page 28. After the first day of operation,
retorque the fasteners. Although pump use varies, a
general guideline is to retorque fasteners every two
months.
Grounding
FIRE AND EXPLOSION HAZARD
This pump must be grounded. Before
operating the pump, ground the system
as explained below. Also, read the sec-
tion FIRE AND EXPLOSION HAZARD,
on page 3.
WARNING
To reduce the risk of static sparking, ground the pump
and all other equipment used or located in the pumping
area. Check your local electrical code for detailed
grounding instructions for your area and type of equip-
ment. Ground all of this equipment:
Pump: Connect a ground wire and clamp as shown
in Fig. 1. Loosen the grounding screw (W). Insert
one end of a 12 ga (1.5 mm) minimum ground wire
(Y) behind the grounding screw and tighten the
screw securely. Connect the clamp end of the
ground wire to a true earth ground. Order Part
No. 222011 Ground Wire and Clamp.
Fig. 1
Y
W
02646B
Air and fluid hoses: Use only grounded hoses with
a maximum of 500 ft (150 m) combined hose
length to ensure grounding continuity.
Air compressor: Follow the manufacturer’s recom-
mendations.
All solvent pails used when flushing: Follow the
local code. Use only metal pails, which are conduc-
tive. Do not place the pail on a non-conductive
surface, such as paper or cardboard, which inter-
rupts the grounding continuity.
Fluid supply container: Follow the local code.

308441 5
Installation
Mountings
CAUTION
The pump exhaust air may contain contaminants.
Ventilate to a remote area if the contaminants
could affect your fluid supply. See Air Exhaust
Ventilation on page 8.
1. Be sure the mounting surface can support the
weight of the pump, hoses, and accessories, as
well as the stress caused during operation.
2. For all mountings, be sure the pump is bolted
directly to the mounting surface.
3. For ease of operation and service, mount the
pump so the air valve cover (2), air inlet, and fluid
inlet and outlet ports are easily accessible.
4. Rubber Foot Mounting Kit 236452 is available to
reduce noise and vibration during operation.
Air Line
WARNING
A bleed-type master air valve (B) is required in
your system to relieve air trapped between this
valve and the pump. Trapped air can cause the
pump to cycle unexpectedly, which could result in
serious injury, including splashing in the eyes or on
the skin, injury from moving parts, or contamination
from hazardous fluids. See Fig. 2.
1. Install the air line accessories as shown in Fig. 2.
Mount these accessories on the wall or on a
bracket. Be sure the air line supplying the acces-
sories is grounded.
a. Install an air regulator (C) and gauge to control
the fluid pressure. The fluid outlet pressure will
be the same as the setting of the air regulator.
b. Locate one bleed-type master air valve (B)
close to the pump and use it to relieve trapped
air. See the WARNING above. Locate the
other master air valve (E) upstream from all air
line accessories and use it to isolate them
during cleaning and repair.
c. The air line filter (F) removes harmful dirt and
moisture from the compressed air supply.
2. Install a grounded, flexible air hose (A) between
the accessories and the 1/2 npt(f) pump air inlet
(N). See Fig. 3. Use a minimum 1/2 in. (13 mm) ID
air hose. Screw an air line quick disconnect cou-
pler (D) onto the end of the air hose (A), and screw
the mating fitting into the pump air inlet snugly. Do
not connect the coupler (D) to the fitting until you
are ready to operate the pump.
Installation of Remote Pilot Air Lines
1. Refer to Parts Drawings. Connect air line to pump
as in preceding steps.
2. Connect 1/4 in. O.D. tubing to push type connec-
tors (14) on air motor of pump.
NOTE: by replacing the push type connectors, other
sizes or types of fittings may be used. The new fittings
will require 1/8 in. npt threads.
3. Connect remaining ends of tubes to external air
signal, such as Graco’s Cycleflo (P/N 195264) or
Cycleflo II (P/N195265) controllers.
NOTE: the air pressure at the connectors must be at
least 30% of the air pressure to the air motor for the
pump to operate.
Fluid Suction Line
1. Use grounded fluid hoses (G). The pump fluid
inlet (R) is 1–1/2 in. npt(f). Screw the fluid fitting
into the pump inlet securely.
2. If the fluid inlet pressure to the pump is more than
25% of the outlet working pressure, the ball check
valves will not close fast enough, resulting in
inefficient pump operation.
3. At inlet fluid pressures greater than 15 psi
(0.1 MPa, 1 bar), diaphragm life will be shortened.
4. See the Technical Data on page 30 for maximum
suction lift (wet and dry).

6 308441
Installation
Fluid Outlet Line
WARNING
A fluid drain valve (J) is required to relieve pres-
sure in the hose if it is plugged. The drain valve
reduces the risk of serious injury, including splash-
ing in the eyes or on the skin, or contamination
from hazardous fluids when relieving pressure.
Install the valve close to the pump fluid outlet. See
Fig. 2.
1. Use grounded fluid hoses (L). The pump fluid
outlet (S) is 1–1/2 in. npt(f). Screw the fluid fitting
into the pump outlet securely.
2. Install a fluid drain valve (J) near the fluid outlet.
See the WARNING above.
3. Install a shutoff valve (K) in the fluid outlet line.
KEY
A Air supply hose
B Bleed-type master air valve
(required for pump)
C Air regulator
D Air line quick disconnect
E Master air valve (for accessories)
F Air line filter
G Fluid suction hose
H Fluid supply
J Fluid drain valve (required)
K Fluid shutoff valve
L Fluid hose
R 1.5 npt(f) fluid inlet port
S 1.5 npt(f) fluid outlet port
Y Ground wire (required; see page 4
for installation instructions)
Fig. 2
TYPICAL FLOOR-MOUNT INSTALLATION
Y
J
F
BE
C
A
DKL
G
H
R
S
03265B
Muffler not included
on Model No. 253485

308441 7
Installation
Changing the Orientation of the Fluid Inlet
and Outlet Ports
The pump is shipped with the fluid inlet (R) and outlet
(S) ports facing the same direction. See Fig. 3. To
change the orientation of the inlet and/or outlet port:
1. Remove the screws (106) holding the inlet (102)
and/or outlet (103) manifold to the covers (101).
2. Reverse the manifold and reattach. Install the
screws, and torque according to the torque notes
in Fig. 3.
Fig. 3
1Apply medium-strength (blue) Loctiteor equivalent to the
threads. Torque to 120–150 in-lb (14–17 Nm). See Torque
Sequence, page 28.
KEY
N 1/2 npt(f) air inlet port
P Muffler. Air exhaust port
is 3/4 npt(f) . (Not included
on Model No. 253485)
R 1.5 npt(f) fluid
inlet port
S 1.5 npt(f) fluid
outlet port
101Covers
102 Fluid inlet manifold
103 Fluid outlet manifold
106 Manifold and cover screw
s
112 Bottom cover screws
N
P
R
S
2
Aluminum Model Shown
1
106
106
102
103
101
112 2
2Apply medium-strength (blue) Loctiteor equivalent to the
threads. Torque to 190–220 in-lb (22–25 Nm). See Torque
Sequence, page 28.
03263B
Fluid Pressure Relief Valve
Some systems may require installation of a pres-
sure relief valve at the pump outlet to prevent
overpressurization and rupture of the pump or
hose. See Fig. 4.
Thermal expansion of fluid in the outlet line can
cause overpressurization. This can occur when
using long fluid lines exposed to sunlight or ambi-
ent heat, or when pumping from a cool to a warm
area (for example, from an underground tank).
Overpressurization can also occur if the Husky
pump is being used to feed fluid to a piston pump,
and the intake valve of the piston pump does not
close, causing fluid to back up in the outlet line.
CAUTION
Fig. 4
1
2Connect fluid inlet line here.
KEY
R 1.5 npt(f) fluid inlet port
S 1.5 npt(f) fluid outlet port
V Pressure relief valve (Order Part No. 112119 for stainless steel
pumps)
R
S
Connect fluid outlet line here.
1
2
3
Install valve between fluid inlet and outlet ports.
V
03461B
4 Muffler not included on Model No. 253485
3
4

8 308441
Installation
Air Exhaust Ventilation
FIRE AND EXPLOSION HAZARD
Be sure to read and follow the warnings
and precautions regarding TOXIC
FLUID HAZARD, and FIRE OR EXPLO-
SION HAZARD on page 3, before op-
erating this pump.
Be sure the system is properly ventilated for your
type of installation. You must vent the exhaust to a
safe place, away from people, animals, food handl-
ing areas, and all sources of ignition when pumping
flammable or hazardous fluids.
Diaphragm failure will cause the fluid being
pumped to exhaust with the air. Place an appropri-
ate container at the end of the air exhaust line to
catch the fluid. See Fig. 5.
WARNING
The air exhaust port is 3/4 npt(f). Do not restrict the air
exhaust port. Excessive exhaust restriction can cause
erratic pump operation.
If the muffler (P) is installed directly to the air exhaust
port, apply PTFE thread tape or anti–seize thread
lubricant to the muffler threads before assembly.
To provide a remote exhaust:
1. Remove the muffler (P) from the pump air exhaust
port.
2. Install a grounded air exhaust hose (T) and con-
nect the muffler (P) to the other end of the hose.
The minimum size for the air exhaust hose is 3/4
in. (19 mm) ID. If a hose longer than 15 ft (4.57 m)
is required, use a larger diameter hose. Avoid
sharp bends or kinks in the hose. See Fig. 5.
3. Place a container (U) at the end of the air exhaust
line to catch fluid in case a diaphragm ruptures.
03267A
Fig. 5
KEY
A Air supply line
B Bleed-type master air valve
(required for pump)
C Air regulator
D Air line quick disconnect
E Master air valve (for accessories)
F Air line filter
P Muffler (not included on
Model No. 253485)
T Grounded air exhaust hose
U Container for remote air exhaust
FBEC
A
D
VENTING EXHAUST AIR
P
T
U

308441 9
Operation
Pressure Relief Procedure
PRESSURIZED EQUIPMENT HAZARD
The equipment stays pressurized until pressure is
manually relieved. To reduce the risk of serious
injury from pressurized fluid, accidental spray from
the gun or splashing fluid, follow this procedure
whenever you:
Are instructed to relieve pressure,
Stop pumping,
Check, clean or service any system equipment,
Install or clean fluid nozzles.
WARNING
1. Shut off the air to the pump.
2. Open the dispensing valve, if used.
3. Open the fluid drain valve to relieve all fluid pres-
sure, having a container ready to catch the drain-
age.
Flush the Pump Before First Use
The pump was tested with lightweight oil, which is left
in the fluid passages to protect parts. To avoid contam-
inating your fluid with oil, flush the pump with a com-
patible solvent before using the equipment. Follow the
steps under Starting and Adjusting the Pump.
Starting and Adjusting the Pump
TOXIC FLUID HAZARD
To reduce the risk of serious injury,
splashing in the eyes or on the skin, and
toxic fluid spills, never move or lift a
pump under pressure. If dropped, the fluid section
may rupture. Always follow the Pressure Relief
Procedure above before lifting the pump.
WARNING
1. Be sure the pump is properly grounded. Refer to
Grounding on page 4.
2. Check all fittings to be sure they are tight. Be sure
to use a compatible liquid thread sealant on all
male threads. Tighten the fluid inlet and outlet
fittings securely.
3. Place the suction tube (if used) in the fluid to be
pumped.
NOTE: If the fluid inlet pressure to the pump is more
than 25% of the outlet working pressure, the ball check
valves will not close fast enough, resulting in inefficient
pump operation.
4. Place the end of the fluid hose (L) into an appropri-
ate container.
5. Close the fluid drain valve (J). See Fig. 2.
6. Close the pump air regulator (C). Open all bleed-
type master air valves (B, E).
7. If the fluid hose has a dispensing device, hold it
open while continuing with the following step.
8. Slowly open the air regulator (C) until the pump
starts to cycle. Allow the pump to cycle slowly until
all air is pushed out of the lines and the pump is
primed.
If you are flushing, run the pump long enough to
thoroughly clean the pump and hoses. Close the
air regulator. Remove the suction tube from the
solvent and place it in the fluid to be pumped.
Operation of Remote Piloted Pumps
1. Follow preceding steps 1 through 7 of Starting
and Adjusting Pump.
2. Open air regulator (C).
WARNING
The pump may cycle once before the external sig-
nal is applied. Injury is possible. If pump cycles,
wait until end before proceeding.
3. Pump will operate when air pressure is alternately
applied and relieved to push type connectors (14).
NOTE: Leaving air pressure applied to the air motor for
extended periods when the pump is not running may
shorten the diaphragm life. Using a 3–way solenoid
valve to automatically relieve the pressure on the air
motor when the metering cycle is complete prevents
this from occurring.
Pump Shutdown
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure at left.
At the end of the work shift, relieve the pressure.

10 308441
Notes

308441 11
Maintenance
Lubrication
The air valve is designed to operate unlubricated,
however if lubrication is desired, every 500 hours of
operation (or monthly) remove the hose from the pump
air inlet and add two drops of machine oil to the air
inlet.
CAUTION
Do not over-lubricate the pump. Oil is exhausted
through the muffler, which could contaminate your
fluid supply or other equipment. Excessive lubrica-
tion can also cause the pump to malfunction.
Tightening Threaded Connections
Before each use, check all hoses for wear or damage,
and replace as necessary. Check to be sure all
threaded connections are tight and leak–free.
Check fasteners. Tighten or retorque as necessary.
Although pump use varies, a general guideline is to
retorque fasteners every two months. See Torque
Sequence, page 28.
Flushing and Storage
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 9.
Flush the pump often enough to prevent the fluid you
are pumping from drying or freezing in the pump and
damaging it. Use a compatible solvent.
Always flush the pump and relieve the pressure before
storing it for any length of time.

12 308441
Troubleshooting
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 9.
Relieve the pressure before checking or servicing
the equipment.
Check all possible problems and causes before
disassembling the pump.
PROBLEM CAUSE SOLUTION
Pump cycles at stall or fails to hold
pressure at stall. Worn check valve balls (301), seats (201) or o-rings (202). Replace. See page 16.
Pump will not cycle, or cycles once
and stops. Air valve is stuck or dirty. Disassemble and clean air valve. See pages 14–15. Use filtered air.
Check valve ball (301) severely
worn and wedged in seat (201) or
manifold (102 or 103).
Replace ball and seat. See page
16.
Check valve ball (301) is wedged
into seat (201), due to overpressur-
ization.
Install Pressure Relief Valve
(see page 7).
Dispensing valve clogged. Relieve pressure and clear valve.
Pump operates erratically. Clogged suction line. Inspect; clear.
Sticky or leaking balls (301). Clean or replace. See page 16.
Diaphragm ruptured. Replace. See pages 17–19.
Restricted exhaust. Remove restriction.
Air bubbles in fluid. Suction line is loose. Tighten.
Diaphragm ruptured. Replace. See pages 17–19.
Loose inlet manifold (102), dam-
aged seal between manifold and
seat (201), damaged o-rings (202).
Tighten manifold bolts (106) or re-
place seats (201) or o-rings (202).
See page 16.
Loose diaphragm shaft bolt (107). Tighten or replace. See pages
17–19.
Damaged o-ring (108). Replace. See pages 17–19.

308441 13
Troubleshooting
PROBLEM CAUSE SOLUTION
Fluid in exhaust air. Diaphragm ruptured. Replace. See pages 17–19.
Loose diaphragm shaft bolt (107). Tighten or replace. See pages
17–19.
Damaged o-ring (108). Replace. See pages 17–19.
Pump exhausts excessive air at
stall. Worn air valve block (7), o-ring (6), plate (8), pilot block (18), u-cups
(10), or pilot pin o-rings (17).
Repair or replace. See pages
14–15.
Worn shaft seals (402). Replace. See pages 17–19.
Pump leaks air externally. Air valve cover (2) or air valve cover
screws (3) are loose. Tighten screws. See page 15.
Air valve gasket (4) or air cover
gasket (22) is damaged. Inspect; replace. See pages 14–15, 20–21.
Air cover screws (25) are loose. Tighten screws. See pages 20–21.
Pump leaks fluid externally from ball
check valves. Loose manifolds (102, 103), dam- aged seal between manifold and
seat (201), damaged o-rings (202).
Tighten manifold bolts (106) or re-
place seats (201) or o-rings (202).
See page 16.

14 308441
Service
Repairing the Air Valve
Tools Required
Torque wrench
Torx (T20) screwdriver or 7 mm (9/32 in.) socket
wrench
Needle-nose pliers
O-ring pick
Lithium base grease
NOTE: Air Valve Repair Kits 236273 (aluminum center
housing models) and 255061 (sst center housing
models) are available. Refer to page 23. Parts included
in the kit are marked with a symbol, for example (4).
Use all the parts in the kit for the best results.
Disassembly
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 9.
1. Relieve the pressure.
2. With a Torx (T20) screwdriver or 7 mm (9/32 in.)
socket wrench, remove the six screws (3), air
valve cover (2), and gasket (4). See Fig. 6.
3. Move the valve carriage (5) to the center position
and pull it out of the cavity. Remove the valve
block (7) and o-ring (6) from the carriage.
Using a needle-nose pliers, pull the pilot block (18)
straight up and out of the cavity. See Fig. 7.
4. Pull the two actuator pistons (11) out of the bear-
ings (12). Remove the u-cup packings (10) from
the pistons. Pull the pilot pins (16) out of the
bearings (15). Remove the o-rings (17) from the
pilot pins. See Fig. 8.
5. Inspect the valve plate (8) in place. If damaged,
use a Torx (T20) screwdriver or 7 mm (9/32 in.)
socket wrench to remove the three screws (3).
Remove the valve plate (8) and, on aluminum
center housing models only, remove the seal (9).
See Fig. 9.
6. Inspect the bearings (12, 15) in place. See Fig. 8.
The bearings are tapered and, if damaged, must
be removed from the outside. This requires disas-
sembly of the fluid section. See page 20.
7. Clean all parts and inspect for wear or damage.
Replace as needed. Reassemble as explained on
page 15.
Torque to 50–60 in-lb
(5.6–6.8 Nm).
Fig. 6
3
2
4
2
2
03268B
1Muffler not included on
Model No. 253485
1
03269
18 5
Fig. 7
1
2
See Detail at right.
Grease.
3 Grease lower face.
1
7
6
5
2
3
3
11

308441 15
Service
03270
Fig. 8
17 16
11
10
12
15
1
2
Insert narrow end first.
Grease.
3Install with lips facing
narrow end of piston (11).
4Insert wide end first.
1
2
3
4
2
03271
1
28
9
3
Rounded side must face down
(aluminum center housing mod-
els only).
Tighten screws until
they bottom out on the
housing.
Fig. 9
1
2
Reassembly
1. If you removed the bearings (12, 15), install new
ones as explained on page 20. Reassemble the
fluid section.
2. On aluminum center housing models, install the
valve plate seal (9) into the groove at the bot-
tom of the valve cavity. The rounded side of the
seal must face down into the groove. See Fig. 9.
3. Install the valve plate (8) in the cavity. On alumi-
num center housing models, the plate is reversible,
so either side can face up. Install the three screws
(3), using a Torx (T20) screwdriver or 7 mm (9/32
in.) socket wrench. Tighten until the screws bottom
out on the housing. See Fig. 9.
4. Install an o-ring (17) on each pilot pin (16).
Grease the pins and o-rings. Insert the pins into
the bearings (15), narrow end first. See Fig. 8.
5. Install a u-cup packing (10) on each actuator
piston (11), so the lips of the packings face the
narrow end of the pistons. See Fig. 8.
6. Lubricate the u-cup packings (10) and actuator
pistons (11). Insert the actuator pistons in the
bearings (12), wide end first. Leave the narrow
end of the pistons exposed. See Fig. 8.
7. Grease the lower face of the pilot block (18) and
install so its tabs snap into the grooves on the
ends of the pilot pins (16). See Fig. 7.
8. Grease the o-ring (6) and install it in the valve
block (7). Push the block onto the valve carriage
(5). Grease the lower face of the valve block. See
Fig. 7.
9. Install the valve carriage (5) so its tabs slip into the
grooves on the narrow end of the actuator pistons
(11). See Fig. 7.
10. Align the valve gasket (4) and cover (2) with the
six holes in the center housing (1). Secure with six
screws (3), using a Torx (T20) screwdriver or 7
mm (9/32 in.) socket wrench. Torque to 50–60 in-lb
(5.6–6.8 Nm). See Fig. 6.

16 308441
Service
Ball Check Valve Repair
Tools Required
Torque wrench
13 mm socket wrench
O-ring pick
Disassembly
NOTE: A Fluid Section Repair Kit is available. Refer to
page 23 to order the correct kit for your pump. Parts
included in the kit are marked with an asterisk, for
example (201*). Use all the parts in the kit for the best
results.
NOTE: To ensure proper seating of the balls (301),
always replace the seats (201) when replacing the
balls. Also, on some models, replace the o-rings (202).
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 9.
1. Relieve the pressure. Disconnect all hoses.
2. Remove the pump from its mounting.
3. Using a 13 mm socket wrench, remove the four
bolts (106) holding the outlet manifold (103) to the
fluid covers (101). See Fig. 10.
4. Remove the o-rings (202, not used on some
models), seats (201), and balls (301) from the
manifold.
5. Turn the pump over and remove the inlet manifold
(102). Remove the o-rings (202, not used on some
models), seats (201), and balls (301) from the fluid
covers (101).
Reassembly
1. Clean all parts and inspect for wear or damage.
Replace parts as needed.
2. Reassemble in the reverse order, following all
notes in Fig. 10. Be sure the ball checks are
assembled exactly as shown. The arrows (A) on
the fluid covers (101) must point toward the outlet
manifold (103).
03272B
Fig. 10
1
2
Apply medium-strength (blue) Loctiteor equivalent to the
threads. Torque to 120–150 in-lb (14–17 Nm). See Torque
Sequence, page 28.
Arrow (A) must point toward
outlet manifold (103).
106
103
101
A
201*
301*
106
102
201*
301*
2
1
1
202*
202*
3Not used on some models.
3
3
4Beveled seating surface
must face ball (301).
4
4
3

308441 17
Service
Diaphragm Repair
Tools Required
Torque wrench
13 mm socket wrench
15 mm socket wrench (aluminum models) or
1 in. socket wrench (stainless steel models)
19 mm open–end wrench
O-ring pick
Lithium-base grease
Disassembly
NOTE: A Fluid Section Repair Kit is available. Refer to
page 23 to order the correct kit for your pump. Parts
included in the kit are marked with an asterisk, for
example (401*). Use all the parts in the kit for the best
results.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 9.
1. Relieve the pressure.
2. Remove the manifolds and disassemble the ball
check valves as explained on page 16.
3. Using a 13 mm socket wrench, remove the screws
(106 and 112) holding the fluid covers (101) to the
air covers (23). Pull the fluid covers (101) off the
pump. See Fig. 11.
Fig. 11
1
2
23
101
A2
B
Arrow (A) must point toward air valve (B).
Apply medium-strength (blue) Loctiteor equivalent to
the threads. Torque to 190–220 in-lb (22–25 Nm).
See Torque Sequence, page 28.
1
106
112 1
03273C
3Muffler not included on Model No. 253485.
3

18 308441
Service
4. Loosen but do not remove the diaphragm shaft
bolts (107), using a 15 mm socket wrench (1 in. on
stainless steel models) on both bolts.
5. Unscrew one bolt from the diaphragm shaft (24)
and remove the o-ring (108), fluid side diaphragm
plate (105), PTFE diaphragm (403, used on PTFE
models only), diaphragm (401), and air side dia-
phragm plate (104). See Fig. 12.
6. Pull the other diaphragm assembly and the dia-
phragm shaft (24) out of the center housing (1).
Hold the shaft flats with a 19 mm open–end
wrench, and remove the bolt (107) from the shaft.
Disassemble the remaining diaphragm assembly.
7. Inspect the diaphragm shaft (24) for wear or
scratches. If it is damaged, inspect the bearings
(19) in place. If the bearings are damaged, refer to
page 20.
8. Reach into the center housing (1) with an o-ring
pick and hook the u-cup packings (402), then pull
them out of the housing. This can be done with the
bearings (19) in place.
9. Clean all parts and inspect for wear or damage.
Replace parts as needed.
Reassembly
1. Install the shaft u-cup packings (402*) so the lips
face out of the housing (1). Lubricate the pack-
ings. See Fig. 12.
2. Install the diaphragm assembly on one end of the
shaft (24) as follows:
a. Install the o-ring (108*) on the shaft bolt (107).
b. Install the fluid side diaphragm plate (105) on
the bolt so the rounded side faces in, toward
the diaphragm (401).
c. On PTFE models only, install the PTFE dia-
phragm (403*). Make certain the side marked
AIR SIDE faces the center housing (1).
d. Install the diaphragm (401*) on the bolt. Make
certain the side marked AIR SIDE faces the
center housing (1).
e. Install the air side diaphragm plate (104) so
the recessed side faces the diaphragm (401).
f. Apply medium-strength (blue) Loctiteor
equivalent to the bolt (107) threads. Screw the
bolt (107) into the shaft (24) hand tight.
3. Grease the length and ends of the diaphragm shaft
(24), and slide it through the housing (1).
4. Assemble the other diaphragm assembly to the
shaft as explained in step 2.
5. Hold one shaft bolt (107) with a wrench and torque
the other bolt to 20–25 ft-lb (27–34 Nm) at 100
rpm maximum.
6. Align the fluid covers (101) and the center housing
(1) so the arrows (A) on the covers face the same
direction as the air valve (B). Apply medium-
strength (blue) Loctiteor equivalent to the
threads of screws (106) and (112), and secure the
covers with the screws handtight. Install the
longer screws (112) in the bottom holes of the
covers. See Fig. 11. Using a 13 mm socket
wrench, torque the screws oppositely and evenly
to 190–220 in-lb (22–25 Nm). See Torque Se-
quence, page 28.
7. Reassemble the ball check valves and manifolds
as explained on page 16.

308441 19
Service
03275A
03274A
Fig. 12
1
3
4
2
24 104
403*
401*
108*
107
24
24 104 401*
403*
107
105
19 402*
Cutaway View, with Diaphragms in Place Cutaway View, with Diaphragms Removed
1
Lips face out of housing (1).
Rounded side faces diaphragm (401).
Air Side must face center housing (1).
1
Grease.
Apply medium-strength (blue) Loctiteor equiva-
lent. Torque to 20 to 25 ft-lb (27 to 34 N-m) at 100
rpm maximum.
Used on pumps with PTFE diaphragms only.
5
6
1
2
3
3
3
3
1
4
4
4
5
5
6
6
105 2
7Recessed side faces diaphragm (401).
7
7
03276C
8Muffler not included on Model No. 253485.
8

20 308441
Service
Bearing and Air Gasket Removal
Tools Required
Torque wrench
10 mm socket wrench
Bearing puller
O-ring pick
Press, or block and mallet
Disassembly
NOTE: Do not remove undamaged bearings.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 9.
1. Relieve the pressure.
2. Remove the manifolds and disassemble the ball
check valves as explained on page 16.
3. Remove the fluid covers and diaphragm assem-
blies as explained on page 17.
NOTE: If you are removing only the diaphragm shaft
bearing (19), skip step 4.
4. Disassemble the air valve as explained on page
14.
5. Using a 10 mm socket wrench, remove the screws
(25) holding the air covers (23) to the center
housing (1). See Fig. 13.
6. Remove the air cover gaskets (22). Always replace
the gaskets with new ones.
7. Use a bearing puller to remove the diaphragm
shaft bearings (19), air valve bearings (12) or pilot
pin bearings (15). Do not remove undamaged
bearings.
8. If you removed the diaphragm shaft bearings (19),
reach into the center housing (1) with an
o-ring pick and hook the u-cup packings (402),
then pull them out of the housing. Inspect the
packings. See Fig. 12.
Reassembly
1. If removed, install the shaft u-cup packings (402*)
so the lips face out of the housing (1).
2. The bearings (12, 15, and 19) are tapered and can
only be installed one way. Insert the bearings into
the center housing (1), tapered end first. Using a
press or a block and rubber mallet, press-fit the
bearing so it is flush with the surface of the center
housing.
3. Reassemble the air valve as explained on page
15.
4. Align the new air cover gasket (22) so the pilot pin
(16) protruding from the center housing (1) fits
through the proper hole (H) in the gasket.
5. Align the air cover (23) so the pilot pin (16) fits in
the middle hole (M) of the three small holes near
the center of the cover. Apply medium-strength
(blue) Loctiteor equivalent to the threads of
screws (25), and install the screws handtight. See
Fig. 13. Using a 10 mm socket wrench, torque the
screws oppositely and evenly to 130–150 in-lb
(15–17 Nm).
6. Install the diaphragm assemblies and fluid covers
as explained on page 17.
7. Reassemble the ball check valves and manifolds
as explained on page 16.