Graco Dura-Flo 750 User manual

308–417
Rev. C
Supersedes B
First choice when
quality counts. 
05241
05242
Model 236–459
Model 237–366
INSTRUCTIONS-PARTS LIST
INSTRUCTIONS
This manual contains important
warnings and information.
READ AND KEEP FOR REFERENCE.
CARBON STEEL
Dura-Flo 750 Pumps
With Severe-Duty Rod and Cylinder
Refer to page 2 for a List of Models and the T able of Contents.
GRACO INC. P.O. BOX 1441 MINNEAPOLIS, MN 55440–1441
COPYRIGHT 1995, GRACO INC.
Graco Inc. is registered to I.S. EN ISO 9001

 
List of Models
Pump Part No.
and Series Pump Model
Displacement
Pump Part No.
and Series Ratio
Maximum Fluid
W orking Pressure
Maximum Air
Input Pressure
236–459,
Series A
Kingt238–1 16,
Series A
68:1 42.2 MPa, 422 bar
(6120 psi)
0.63 MPa, 6.3 bar
(90 psi)
237–364,
Series A
Reduced Icing
Quiet King t
238–1 16,
Series A
68:1 42.2 MPa, 422 bar
(6120 psi)
0.63 MPa, 6.3 bar
(90 psi)
237–366,
Series A
Bulldogr 236–455,
Series A
33:1 22.8 MPa, 228 bar
(3300 psi)
0.7 MPa, 7 bar
(100 psi)
237–582,
Series A
Reduced Icing
Quiet Bulldog r
236–455,
Series A
33:1 22.8 MPa, 228 bar
(3300 psi)
0.7 MPa, 7 bar
(100 psi)
237–370,
Series A
Bulldogr
with riser tube
236–455,
Series A
33:1 22.8 MPa, 228 bar
(3300 psi)
0.7 MPa, 7 bar
(100 psi)
Table of Contents
Warnings 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation/Maintenance 10 . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Chart 13. . . . . . . . . . . . . . . . . . . . . . . . .
Service 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Required Tools 14. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disconnecting the Displacement Pump 14. . . . . . .
Reconnecting the Displacement Pump 14. . . . . . .
Displacement Pump Service 16. . . . . . . . . . . . . . . .
Parts Drawings and Parts Lists 21. . . . . . . . . . . . . . . . . .
Pump Assemblies 21. . . . . . . . . . . . . . . . . . . . . . . . .
Displacement Pump 238–1 16 24. . . . . . . . . . . . . . .
Displacement Pump 236–455 26. . . . . . . . . . . . . . .
Technical Data 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dimensions 31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mounting Hole Layout 31. . . . . . . . . . . . . . . . . . . . . . . . . .
Warranty 32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Graco Phone Number 32. . . . . . . . . . . . . . . . . . . . . . . . . .

 
Symbols
Warning Symbol
WARNING
his 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.
WARNING
INSTRUCTIONS
EQUIPMENT MISUSE HAZARD
Equipment misuse can cause the equipment to rupture or malfunction and result in serious injury .
D
This equipment is for professional use only .
D
Read all instruction manuals, tags, and labels before operating the equipment.
D Use the equipment only for its intended purpose. If you are uncertain about usage, call your Graco
distributor.
D
Do not alter or modify this equipment. Use only genuine Graco parts and accessories.
D Check equipment daily . Repair or replace worn or damaged parts immediately .
D Do not exceed the maximum working pressure of the lowest rated system component. Refer to the
T echnical Data on pages 28 and 29 for the maximum working pressure of this equipment.
D Use fluids and solvents which are compatible with the equipment wetted parts. Refer to the Tech-
nical Data section of all equipment manuals. Read the fluid and solvent manufacturer ’ s warnings.
D Do not use hoses to pull equipment.
D Route hoses away from traffic areas, sharp edges, moving parts, and hot surfaces. Do not expose
Graco hoses to temperatures above 82 _ C (180 _ F) or below –40 _ C (–40 _F).
DW
ear hearing protection when operating this equipment.
D Do not lift pressurized equipment.
D Comply with all applicable local, state, and national fire, electrical, and safety regulations.

 
WARNING
INJECTION HAZARD
Spray from the gun, hose leaks, or ruptured components can inject fluid into your body and cause
extremely serious injury
, including the need for amputation. Fluid splashed in the eyes or on the skin
can also cause serious injury .

Fluid injected into the skin might look like just a cut, but it is a serious injury . Get immediate medi -
cal attention.

Do not point the gun at anyone or at any part of the body .

Do not put your hand or fingers over the spray tip.
 Do not stop or deflect leaks with your hand, body , glove or rag.
 Do not “blow back” fluid; this is not an air spray system.
 Always have the tip guard and the trigger guard on the gun when spraying.
 Check the gun dif fuser operation weekly . Refer to the gun manual.
 Be sure the gun trigger safety operates before spraying.
 Lock the gun trigger safety when you stop spraying.
 Follow the Pressure Relief Procedure on page 10 whenever you: are instructed to relieve pres -
sure; stop spraying; clean, check, or service the equipment; and install or clean the spray tip.
T ighten all fluid connections before operating the equipment.
 Check the hoses, tubes, and couplings daily . Replace worn, damaged, or loose parts immediately .
Permanently coupled hoses cannot be repaired; replace the entire hose.
 Use only Graco approved hoses. Do not remove any spring guard that is used to help protect the
hose from rupture caused by kinks or bends near the couplings.
MOVING P ARTS HAZARD
Moving parts, such as the air motor piston, can pinch or amputate your fingers.
 Keep clear of all moving parts when starting or operating the pump.
 Before servicing the equipment, follow the Pressure Relief Procedure on page 10 to prevent the
equipment from starting unexpectedly
.

308-417 5
WARNING
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 and the object being sprayed. Refer to Grounding on page 7.
 If there is any static sparking or you feel an electric shock while using this equipment, stop spray-
ing 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.
 Keep the spray area free of debris, including solvent, rags, and gasoline.
 Electrically disconnect all equipment in the spray area.
 Extinguish all open flames or pilot lights in the spray area.
 Do not smoke in the spray area.
 Do not turn on or of f any light switch in the spray area while operating or if fumes are present.
 Do not operate a gasoline engine in the spray area.
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 .

6 308-417
Notes

 
Installation
General Information
NOTE: Reference numbers and letters in parentheses
in the text refer to the callouts in the figures and the
parts drawing.
NOTE: Always use Genuine Graco Parts and Acces -
sories, available from your Graco distributor . Refer to
the Product Data Sheet, Form No. 305–722 for Bulldog
Pumps and Form No. 305–723 for King Pumps. If you
supply your own accessories, be sure they are ade -
quately sized and pressure rated for your system.
Grounding
WARNING
FIRE AND EXPLOSION HAZARD
Before operating the pump, ground the
system as explained below . Also read
the section FIRE AND EXPLOSION
HAZARD on page 5.
1. Pump: use a ground wire and clamp. See Fig. 1.
Loosen the grounding lug locknut (W) and washer
(X). Insert one end of a 1.5 mm  (12 ga) minimum
ground wire (Y) into the slot in lug (Z) and tighten
the locknut securely . Connect the other end of the
wire to a true earth ground. Order Part No.
237–569 Ground Wire and Clamp.
Fig. 1
W
X
Y
Z
0864
2. Air and fluid hoses: use only electrically conductive
hoses.
3.
Air compressor: follow manufacturer ’ s recommen -
dations.
4.
Spray gun: ground through connection to a prop -
erly grounded fluid hose and pump.
5. Fluid supply container: follow your local code.
6. Object being sprayed: follow your local code.
7. Solvent pails used when flushing: follow your local
code. Use only metal pails, which are conductive,
placed on a grounded surface. Do not place the
pail on a nonconductive surface, such as paper or
cardboard, which interrupts the grounding continu -
ity.
8.
T o maintain grounding continuity when flushing or
relieving pressure , hold a metal part of the spray
gun firmly to the side of a grounded metal pail,
then trigger the gun.
System Accessories
Fig. 2 is only a guide for selecting and installing sys -
tem components and accessories. Contact your Graco
distributor for assistance in designing a system to suit
your particular needs.
Air and Fluid Hoses
Be sure all air hoses (H) and fluid hoses (N and P) are
properly sized and pressure-rated for your system.
Use only electrically conductive hoses. Fluid hoses
must have spring guards on both ends. Use a whip
hose (P) and a swivel (R) between the main fluid hose
(N) and the gun (S) to allow freer gun movement.
Mounting Accessories
Mount the pump (A) to suit the type of installation
planned. Fig. 2 illustrates a wall mount system. Pump
dimensions and the mounting hole layout are shown
on page 31.
If you are using a floor stand, refer to its separate
manual for installation and operation instructions.

 
Installation
System Accessories (continued)
WARNING
A bleed-type master air valve (E) and a fluid drain
valve (M) are required in your system. These
accessories help reduce the risk of serious injury ,
including fluid injection and splashing of fluid in the
eyes or on the skin, and injury from moving parts if
you are adjusting or repairing the pump.
The bleed-type master air valve relieves air trapped
between this valve and the pump after the air is
shut of f. T rapped air can cause the pump to cycle
unexpectedly . Locate the valve close to the pump.
Order Part No. 107–141.
The fluid drain valve assists in relieving fluid pres -
sure in the displacement pump, hose, and gun.
T riggering the gun to relieve pressure may not be
suf ficient. Order Part No. 210–658.
Air Line Accessories
Install the following accessories in the locations shown
in Fig. 2, using adapters as necessary:
An air line lubricator (D) provides automatic air
motor lubrication.
A bleed-type master air valve (E) is required in
your system to relieve air trapped between it and
the air motor when the valve is closed (see the
WARNING above). Be sure the bleed valve is eas -
ily accessible from the pump, and is located
downstream from the air regulator .
An
air regulator (F) controls pump speed and out -
let pressure by adjusting the air pressure to the
pump. Locate the regulator close to the pump, but
upstream from the bleed-type master air valve.
A pump runaway valve (C ) senses when the
pump is running too fast and automatically shuts
of f the air to the motor . A pump which runs too fast
can be seriously damaged.
 An air manifold (G) has a 3/4 npsm(f) swivel air
inlet. It mounts to the pump support bracket, and
provides ports for connecting lines to air-powered
accessories.
An
air line filter (J) removes harmful dirt and
moisture from the compressed air supply . Also,
install a drain valve (W) at the bottom of each air
line drop, to drain of
f moisture.
A second bleed-type air valve (K) isolates the air
line accessories for servicing. Locate upstream
from all other air line accessories.
Fluid Line Accessories
Install the following accessories in the locations shown
in Fig. 2, using adapters as necessary:
A fluid filter (L) with a 60 mesh (250 micron)
stainless steel element, to filter particles from the
fluid as it leaves the pump.
A fluid drain valve (M), which is required in your
system, helps relieve fluid pressure in the hose
and gun (see the WARNING at left).
A gun (S) dispenses the fluid. The gun shown in
Fig. 2 is an airless spray gun for light to medium
viscosity fluids.
 A gun swivel (R) allows freer gun movement.
A suction kit (T) allows the pump to draw fluid
from a supply container .

308-417 9
Installation
04496
Fig. 2
KEY
APump
BWall
Bracket
C Pump Runaway V alve
D
Air Line Lubricator
EBleed-T ype Master Air V alve
(required, for pump)
F Pump Air Regulator
G Air Manifold
H Electrically Conductive
Air Supply Hose
J Air Line Filter
KBleed-T ype Master Air V alve
(for accessories)
L Fluid Filter
M Fluid Drain V alve (required)
N Electrically Conductive
Fluid Supply Hose
P Fluid Whip Hose
R Gun Swivel
S Airless Spray Gun
T Suction Kit
Y Ground Wire and Clamp
(required; see page 7
for installation instructions)
W Air Line Drain V alve
TYPICAL INSTALLATION
A
B
C
D
E
F
G
H
JK
M
N
P
Y
MAIN
AIR LINE
L
R
S
T
W

 
Operation/Maintenance
Pressure Relief Procedure
WARNING
INJECTION HAZARD
The system pressure must be manually
relieved to prevent the system from
starting or spraying accidentally . Fluid
under high pressure can be injected through the
skin and cause serious injury . T o reduce the risk of
an injury from injection, splashing fluid, or moving
parts, follow the Pressure Relief Procedure
whenever you:
D are instructed to relieve the pressure,
D stop spraying,
D check or service any of the system equipment,
D or install or clean the spray tips.
1. Lock the gun trigger safety .
2.
Shut of f the air supply to the pump.
3. Close the bleed-type master air valve (required in
your system).
4. Unlock the gun trigger safety .
5. Hold a metal part of the gun firmly to the side of a
grounded metal pail, and trigger the gun to relieve
pressure.
6.
Lock the gun trigger safety .
7. Open the drain valve (required in your system),
having a container ready to catch the drainage.
8. Leave the drain valve open until you are ready to
spray again.
If you suspect that the spray tip or hose is completely
clogged, or that pressure has not been fully relieved
after following the steps above, very slowly loosen the
tip guard retaining nut or hose end coupling and relieve
pressure gradually , then loosen completely . Now clear
the tip or hose.
Packing Nut/Wet-Cup
Before starting, fill the packing nut (8) 1/3 full with
Graco Throat Seal Liquid (TSL) or compatible solvent.
See Fig. 3.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure at left.
The packing nut is torqued at the factory and is ready
for operation. If it becomes loose and there is leaking
from the throat packings, relieve pressure, then torque
the nut to 61–75 N S m (45–55 ft-lb) using the supplied
wrench (1 10). Do this whenever necessary . Do not
overtighten the packing nut.
05242
Fig. 3
110
8
1
Model
237–366
Shown
1Torque
to 61–75 N S m
(45–55 ft-lb)

 
Operation/Maintenance
Flush the Pump Before First Use
The pump is tested with lightweight oil, which is left in
to protect the pump parts. If the fluid you are using
may be contaminated by the oil, flush it out with a
compatible solvent. See Flushing on page 12.
Starting and Adjusting the Pump
1. See Fig. 2. Connect the suction kit (T) to the
pump’ s fluid inlet. Place the tube into the fluid
supply.
2.
Close the air regulator (F).
3. Open the pump’ s bleed-type master air valve (E).
4. Hold a metal part of the gun (S) firmly to the side
of a grounded metal pail and hold the trigger open.
5. Slowly open the regulator until the pump starts.
6. Cycle the pump slowly until all air is pushed out
and the pump and hoses are fully primed.
7. Release the gun trigger and lock the trigger safety .
The pump should stall against pressure.
8. If the pump fails to prime properly , open the drain
valve (M). Use the drain valve as a priming valve
until the fluid flows from the valve. Close the valve.
NOTE: When changing fluid containers with the hose
and gun already primed, open the drain valve (M) to
help prime the pump and vent air before it enters the
hose. Close the drain valve when all air is eliminated.
CAUTION
Do not allow the pump to run dry . It will quickly
accelerate to a high speed, causing damage. If your
pump is running too fast, stop it immediately and
check the fluid supply . If the container is empty and
air has been pumped into the lines, refill the con -
tainer and prime the pump and the lines, or flush and
leave it filled with a compatible solvent. Eliminate all
air from the fluid system.
9. With the pump and lines primed, and with ade -
quate air pressure and volume supplied, the pump
will start and stop as you open and close the gun.
In a circulating system, the pump will speed up or
slow down on demand, until the air supply is shut
off.
WARNING
COMPONENT RUPTURE HAZARD
T o reduce the risk of overpressurizing
your system, which could cause compo -
nent rupture and serious injury , never
exceed the specified Maximum Incoming Air Pres -
sure to the pump (see the T echnical Data on
pages 28 and 29).
10. Use the air regulator (F) to control pump speed
and fluid pressure. Always use the lowest air
pressure necessary to get the desired results.
Higher pressures cause premature tip and pump
wear.

 
Operation/Maintenance
Shutdown and Care of the Pump
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 10.
For overnight shutdown, stop the pump at the bottom
of its stroke to prevent fluid from drying on the ex -
posed displacement rod and damaging the throat
packings. Relieve the pressure.
Always flush the pump before the fluid dries on the
displacement rod. See Flushing below .
Flushing
WARNING
FIRE AND EXPLOSION HAZARD
Before flushing, read the section FIRE
AND EXPLOSION HAZARD on page
5. Be sure the entire system and flush -
ing pails are properly grounded. Refer to
Grounding on page 7.
Flush with a fluid that is compatible with the fluid you
are pumping and with the wetted parts in your system.
Check with your fluid manufacturer or supplier for
recommended flushing fluids and flushing frequency .
Always flush the pump before fluid dries on the dis -
placement rod.
CAUTION
Never leave water or water-base fluid in the pump
overnight. If you are pumping water-base fluid, flush
with water first, then with a rust inhibitor such as
mineral spirits. Relieve the pressure, but leave the
rust inhibitor in the pump to protect the parts from
corrosion.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 10.
1. Relieve the pressure.
2. Remove the spray tip from the gun.
3. Hold a metal part of the gun firmly to the side of a
grounded metal pail.
4. Start the pump. Always use the lowest possible
fluid pressure when flushing.
5. T rigger the gun.
6. Flush the system until clear solvent flows from the
gun.
7.
Relieve the pressure.

 
Troubleshooting Chart
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 10.
1. Relieve the pressure.
2. Check all possible causes and problems before
disassembling the pump.
PROBLEM CAUSE SOLUTION
The pump fails to oper -
ate.
Valves are closed or clogged. Clear the air line; increase the air supply .
Check that the valves are open.
The fluid hose or gun is obstructed. Clear the hose or gun*;
use a hose with a larger ID.
Fluid has dried on the displacement rod. Clean the rod; always stop the pump at the bottom
of its stroke; keep the wet-cup 1/3 filled with a
compatible
solvent.
Air motor parts are dirty, worn, or dam-
aged.
Clean or repair the air motor; see the separate mo -
tor
manual.
The pump operates,
but
the output is low on
both strokes.
The air line is restricted or the air supply
is inadequate. V alves are closed or
clogged.
Clear the air line; increase the air supply .
Check that the valves are open.
The fluid hose or gun is obstructed;
the fluid hose ID is too small.
Clear the hose or gun*;
use a hose with a larger ID.
Worn packings in the displacement
pump.
Replace the packings.
Air motor parts are dirty, worn, or dam-
aged.
Clean or repair the air motor; see the separate mo -
tor
manual.
Held open or worn intake valve. Clear or service the intake valve.
The pump operates,
but
the output is low on
the downstroke.
Held open or worn intake valve. Clear or service the intake valve.
The pump operates,
but
the output is low on
the upstroke.
Held open or worn piston valve
or packings.
Clear the piston valve; replace the packings.
The pump’ s speed is
erratic
or accelerated.
The fluid supply is exhausted. Refill the supply and prime the pump.
Held open or worn piston valve
or packings.
Clear the piston valve; replace the packings.
Held open or worn intake valve. Clear or service the intake valve.
*T o determine if the fluid hose or gun is obstructed, relieve the pressure. Disconnect the fluid hose and place a
container at the pump fluid outlet to catch any fluid. T
urn on the air just enough to start the pump. If the pump
starts when the air is turned on, the obstruction is in the fluid hose or gun.
NOTE: If you experience air motor icing, call your Graco distributor .

 
Service
Required Tools
DSet of adjustable wrenches
D Large pipe wrench
D 2–3/4 in. socket wrench
DT orque wrench
D Rubber mallet
D O-ring pick
D Large vise
D Plastic or wooden block, approximately
6 in. square x 1 in. thick
D Thread lubricant
D Thread sealant
Disconnecting the Displacement Pump
1. Flush the pump, if possible. Stop the pump at the
bottom of its stroke.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 10.
2. Relieve the pressure.
3. Disconnect the air hose and fluid hose.
4. Disconnect the displacement pump (109) from the
motor (101) as follows. Note the relative position of
the pump’ s fluid outlet (U) to the air inlet (V) of the
motor . If the motor does not require servicing,
leave it attached to its mounting.
CAUTION
Be sure to use two people when lifting, moving, or
disconnecting the entire pump. This pump is too
heavy for one person. If you are disconnecting the
displacement pump from a motor which is still
mounted (for example, on a wall bracket), only one
person is required. The displacement pump weighs
approximately 15 kg (34 lb).
If the pump is mounted on a cart, slowly tip the cart
backward until the handle rests on the ground, then
disconnect the displacement pump.
5. Using an adjustable wrench (or hammer and
punch), unscrew the coupling nut (106) from the
motor shaft (W). Do not lose or drop the coupling
collars (107). See Fig. 4.
NOTE: On Model 237–370, disconnect the riser tube
(1 13) at either the elbow (1 12) or the connector (1 14).
See the Parts Drawing on page 23.
6. Hold the tie rod flats with a wrench to keep the
rods from turning. Unscrew the nuts (108) from the
tie rods (105). Carefully remove the displacement
pump (109) from the motor (101).
7.
Refer to page 16 for displacement pump service.
T o service the air motor , refer to the separate
motor manual, supplied.
Reconnecting the Displacement Pump
1. Make sure the coupling nut (106) and the coupling
collars (107) are in place on the displacement rod
(1). See Fig. 4.
2. Have one person hold the displacement pump
while another reconnects it to the motor (see the
CAUTION at left). Orient the pump’ s fluid outlet
(U) to the air inlet (V) as was noted in step 4 under
Disconnecting the Displacement Pump. Posi -
tion the displacement pump (109) on the tie rods
(105).
NOTE:
On Model 237–370, reconnect the riser tube
(1 13) at either the elbow (1 12) or the connector (1 14).
3. Screw the nuts (108) onto the tie rods (105) and
torque to 68–81 N Sm (50–60 ft-lb).
4.
Screw the coupling nut onto the motor shaft (W)
loosely . Hold the motor shaft flats with a wrench to
keep it from turning. Use an adjustable wrench to
tighten the coupling nut. T orque to 195–210 N Sm
(145–155 ft-lb).
5. Reconnect all hoses. Reconnect the ground wire if
it was disconnected. Fill the packing nut (8) 1/3 full
of Graco Throat Seal Liquid or compatible solvent.
6. T urn on the air supply . Run the pump slowly to
ensure proper operation.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 10.
7. Before returning the pump to production, relieve
the pressure and retorque the packing nut (8) to
61–75 N Sm (45–55 ft-lb).

308-417 15
Service
05243
Fig. 4
101
109
108
107
105
106 110
8
1
2
1
V
U
W
3
3
Model 237–366 Shown
1
2Torque
to 195–210 N  m (145–155 ft-lb)
3T
orque to 68–81 N  m (50–60 ft-lb)
T orque to 61–75 N  m (45–55 ft-lb)

16 308-417
Service
DISPLACEMENT PUMP SERVICE
Disassembly
When disassembling the pump, lay out all the removed
parts in sequence, to ease reassembly
.
NOTE:
Packing Repair Kits are available. For the best
results, use all the new parts in the kit. Kit parts are
marked with an asterisk, for example (3*). Y ou can
also convert the pump to dif ferent packing materials.
Refer to page 25.
1. Place the pump lengthwise in a large vise, with the
jaws on the outlet housing (6) as shown in Fig. 5.
Using the supplied wrench (1 10), loosen, but do
not remove, the packing nut (8).
2. Using a 2–3/4 in. socket or a pipe wrench, un -
screw the intake valve (5) from the intake housing
(7). Be careful to catch the intake ball (13) as you
remove the intake valve, so that it does not fall and
suf fer damage. Remove the seal (1 1) from the
intake valve. Inspect the ball and the seat (D) of
the intake valve for wear or damage.
3. Using a pipe wrench, remove the intake housing
(7) from the cylinder (2).
NOTE:
These instructions are written with the pump
separating at joint A. If it separates at joint B, disas -
semble it at that joint, place the intake housing (7) in a
vise, and continue with step 4.
4. Using a pipe wrench, unscrew the cylinder (2). The
displacement rod (1) may come with the cylinder .
05244A
Fig. 5
1
8
62
7
5
A
B
1
1
D
13* 11*
2
2
3
1Torque
to 325–353 N  m (240–260 ft-lb).
2Lubricate.
3T
orque to 190–217 N  m (140–160 ft-lb).

 
Service
CAUTION
To reduce the possibility of costly damage to the rod
(1) and cylinder (2), always use a plastic or wooden
block to help drive the rod out of the cylinder . Never
hit the rod with a hammer .
5. T urn the cylinder (2) upside down and strike the
top of the rod (1) on a plastic or wooden block until
the piston comes free. Pull the rod and piston from
the cylinder , being careful not to scratch the parts.
See Fig. 6.
04518
1
2
Fig. 6
6. Shine a light into the cylinder (2) to inspect the
inner surface for scoring or wear . Remove the two
seals (1 1) from the cylinder .
7. Place the flats of the piston seat housing (10) in a
vise, as shown in Fig. 7.
8. Using an adjustable wrench, unscrew the piston
ball housing (9) from the piston seat housing. Be
careful to catch the piston ball (12) as you sepa
-
rate the piston seat housing and ball housing, so
that it does not fall and suf fer damage.
9. Examine the displacement rod (1) for scratches or
other damage. Only if the rod needs replace -
ment,
place the piston ball housing (9) in a vise
and unscrew the rod, using an adjustable wrench
on the flats of the rod.
10. Remove the glands and v-packings (P) and the
ball (12) from the piston seat housing (10). Inspect
the ball seat (E) and ball guides (F) for wear or
damage. See Fig. 9.
11. Unscrew the packing nut (8) from the outlet hous -
ing (6). Remove the glands and v-packings (T).
See Fig. 9.
12. Clean all parts with a compatible solvent and
inspect them for wear or damage.
0449404495
Fig. 7
1
91
1
9
1
12*
10
10 1
1Torque
to 258–285 N  m (190–210 ft–lb).

 
Service
Reassembly
1. If it was necessary to remove the piston ball
housing (9) from the displacement rod (1), clean
the threads of the rod and the ball housing, and
apply thread sealant. Screw the ball housing onto
the rod, hand tight. Place the flats of the piston ball
housing in a vise and torque the rod to 258–285
NS m (190–210 ft-lb). See Fig. 9.
2. For the standard leather-packed displacement
pumps 238–1 16 and 236–455, place the piston
packings on the piston seat housing (10) in the
following order , with the lips of the v-packings
facing up:
the female gland (4*), one PTFE r
v-packing (18*), four leather v-packings (19*), and
the male gland (3*). See the Piston Packing Detail
in Fig. 9.
NOTE: T o convert the pump to a dif ferent packing
material, see pages 25 and 27.
3. Place the flats of the piston seat housing (10) in a
vise. Apply thread sealant to the threads of the
piston seat housing. Place the ball (12*) on the
seat. Screw the piston ball housing (9) onto the
piston seat housing hand tight, then torque to
258–285 N S m (190–210 ft-lb). See Fig. 7.
4. For the standard leather-packed displacement
pumps 238–116 and 236–455, lubricate the throat
packings and place them in the outlet housing (6)
in the following order , with the lips of the v-pack-
ings facing down:
the male gland (3*), four
leather v-packings (19*), one PTFE r v-packing
(18*), and the female gland (4*). See the Throat
Packing Detail in Fig. 9.
NOTE: T o convert the pump to a dif ferent packing
material, see pages 25 and 27.
5. Lubricate the threads of the packing nut (8), and
loosely install it in the outlet housing (6).
6. Lubricate the piston packings. Slide the displace -
ment rod (1) and piston assembly down into the
cylinder (2). The cylinder is symmetrical, so either
end may face up. Use a rubber mallet to drive the
rod into the cylinder , until the piston seat housing
(10) is located in the middle of the cylinder .
7.
Install the seal (1 1*) on the top of the cylinder (2).
Lubricate the seal and the top threads of the
cylinder.
8.
Place the outlet housing (6) in a vise, as shown in
Fig. 8. Slide the displacement rod (1) up into the
outlet housing, then screw the cylinder (2) into the
outlet housing handtight. The threads will engage
easily until the seal (1 1*) contacts the sealing
surface of the outlet housing. The top of the rod
will protrude from the packing nut (8).
Fig. 8
05251
1
8
62
7
5
1
1
11* 2
3
1Torque
to 325–353 N S m (240–260 ft-lb).
2Lubricate.
3T
orque to 190–217 N S m (140–160 ft-lb).

308-417 19
Service
04491A
Fig. 9
1
*11
5
13*
10
9
D
E
T
P
8
6
2
*11
*12
7
8 (Ref)
*4
*19
*3
6 (Ref)
4
4
4
5
3
3
2
1
8
Throat Packing Detail
(Leather-Packed Displacement Pump Shown;
see pages 25 and 27 for options.)
S
7
F
Piston Packing Detail
(Leather-Packed Displacement Pump Shown;
see pages 25 and 27 for options.)
*18
*11
4
10
9 (Ref) 2 (Ref)
10 (Ref)
*3
*19
*4
7 (Ref)
*1 1 (Ref)
4
6
*18
9
1
2
3
4
Torque
to 61–75 N  m (45–55 ft-lb).
T orque to 325–353 N  m (240–260 ft-lb).
T orque to 258–285 N  m (190–210 ft-lb).
Apply thread sealant.
Lubricate.
5
6
7
8
Lips face up.
Lips face down.
See the Throat Packing Detail at left.
See the Piston Packing Detail at left.
10 T
orque to 190–217 N  m (140–160 ft-lb).
9

 
Service
9. Install the seal (1 1*) on the intake valve (5). Lubri -
cate the seal and the threads of the intake valve.
10. One end of the intake housing (7) has a rounded
ball cavity (S) on the inside (see Fig. 9). Install the
ball (13*) in this cavity , then screw the intake valve
(5) into the intake housing handtight. See Fig. 10.
The threads will engage easily until the seal con -
tacts the sealing surface of the intake housing.
05245A
7
5
13*
2
1
Fig. 10
1
2
11* 2
Lubricate.
Orient so the end with the ball cavity (S, see Fig. 9)
faces the ball (13*).
11. Install the seal (1 1*) on the bottom of the cylinder
(2). See Fig. 8. Lubricate the seal and the threads
of the cylinder. Screw the intake housing (7) onto
the cylinder handtight. The threads will engage
easily until the seal contacts the sealing surface of
the intake housing.
12. Using a pipe wrench, torque the intake housing (7)
to 325–353 N  m (240–260 ft-lb). This will also
torque the cylinder (2) into the outlet housing (6).
See Fig. 8.
13. Using a 2–3/4 in. socket or a pipe wrench, torque
the intake valve (5) to 190–217 N  m (140–160
ft-lb).
14. T
orque the packing nut (8) to 61–75 N  m (45–55
ft-lb).
15.
Reconnect the displacement pump to the air motor
as explained on page 14.