Graco Dyna-Star A Series Operation manual

308–390
Rev. C
Supersedes Rev. A
Includes Rev. B
First choice when
quality counts. 
INSTRUCTIONS-PARTS LIST
INSTRUCTIONS
This manual contains important
warnings and information.
READ AND KEEP FOR REFERENCE.
Dyna-Star
HYDRAULIC RECIPROCATOR & PUMP
1500 psi (10 MPa, 103 bar) Maximum Hydraulic Input Pressure
375 psi (2.6 MPa, 26 bar) Maximum Fluid Outlet Pressure
1/4:1 RATIO UNIVERSAL PUMP AND RECIPROCATOR
Model 236–753, Series A, stubby length
RECIPROCATOR ONLY
Model 236–751, Series B
WARNING
The pump is designed to dispense lube products
only . Any other fluids can cause unsafe operating
conditions and result in component rupture, fire or
explosion which could cause serious injury , includ -
ing fluid injection.
Table of Contents
Warnings 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reciprocator Repair 14. . . . . . . . . . . . . . . . . . . . . . . . . . .
Displacement Pump Repair 18. . . . . . . . . . . . . . . . . . . . .
Parts List & Drawing
Universal 1/4:1 Ratio Displacement Pump 19. . . . . .
Reciprocator 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessories 22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Data 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dimensional Drawing and Mounting Hole Layout 23. .
Warranty 24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Graco Phone Number 24. . . . . . . . . . . . . . . . . . . . . . . . . .
GRACO INC. P.O. BOX 1441 MINNEAPOLIS, MN 55440–1441
COPYRIGHT 1994, GRACO INC.
Graco Inc. is registered to I.S. EN ISO 9001
Model 236–753 shown
Patent No. 4,383,475
Foreign Patents Pending
Patent 1984 Canada
Brevete 1984


 
Symbols
Warning Symbol
WARNING
This symbol alerts you to the possibility of serious
injury or death if you do not follow the corresponding
instructions.
Caution Symbol
CAUTION
This symbol alerts you to the possibility of damage to
or destruction of equipment if you do not follow the
corresponding 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 you operate the equipment.
D Use the equipment only for its intended purpose. If you are not sure, call your Graco distributor .
D Do not alter or modify this equipment.
D Check equipment daily . Repair or replace worn or damaged parts immediately .
D Do not exceed the maximum working pressure of the lowest rated component in your system.
This equipment has a
1500 psi (10 MPa, 103 bar) maximum hydraulic input pressure and
375 psi (2.6 MPa, 26 bar) maximum fluid outlet pressure.
D Use fluids and solvents that are compatible with the equipment wetted parts. Refer to the
T echnical Data section of all equipment manuals. Read the fluid and solvent manufacturer ’s
warnings.
D
Handle hoses carefully . Do not pull on hoses to move 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).
D
Do not lift pressurized equipment.
D Comply with all applicable local, state, and national fire, electrical, and safety regulations.
WARNING
WARNING


TOXIC FLUID HAZARD
Hazardous fluids 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 .
FLUID INJECTION HAZARD
Spray from the dispensing valve, 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
medical attention.

Do not point the dispensing valve at anyone or at any part of the body .

Do not put your hand or fingers over the end of the dispensing valve.
 Do not stop or deflect leaks with your hand, body , glove, or rag.
 Use only extensions and no-drip tips that are designed for use with your dispensing valve.
 Do not use a low pressure flexible nozzle with this equipment.
 Follow the Pressure Relief Procedure on page 8 if the grease fitting coupler clogs and before
cleaning, checking, or servicing the equipment.
T ighten all fluid connections before you operate the equipment.
 Check the hoses, tubes, and couplings daily . Replace worn or damaged parts immediately . Do
not repair high pressure couplings; you must replace the entire hose.
 Fluid hoses must have spring guards on both ends, to help protect them from rupture caused by
kinks or bends near the couplings.
WARNING
WARNING

4 308-390
MOVING P ARTS HAZARD
Moving parts can pinch or amputate your fingers.
 Keep clear of all moving parts when you start or operate the pump.
 Before you service the equipment, follow the Pressure Relief Procedure on page 8 to prevent
the equipment from starting unexpectedly .
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
spraying 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.
 Before operating this equipment, electrically disconnect all equipment in the spray area.
 Before operating this equipment, 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 spraying or while there are any
fumes in the air .

Do not operate a gasoline engine in the spray area.
WARNING
WARNING
United States Government safety standards have been adopted under the Occupational Safety and Health Act.
Y ou should consult these standards––particularly the General Standards, Part 1910.

5308-390
Installation
KEY
AHydraulic Fluid Control, 236–864
(See Manual 308–395)
B Porous Plug (W eep tube optional)
C Fluid Dispenser Outlet
D Drain V alve (Required)
F Hydraulic Return Line
G Hydraulic Outlet, 3/4 npt
H Return Line Shutof f V alve
J Hydraulic Inlet, 3/8 npt
K Hydraulic Supply Line Shutof f
Valve
L Pressure Gauge
M Pressure Reducing V alve
N Flow Control V alve
P Hydraulic Supply Line (Use only
GRACO hydraulic power supply)
Q Material Supply
R Ground Wire (Required)
SW all Mounting Bracket 236–778
(See Manual 308–394)
Typical Installation – Suction Feed System
Fig. 1 03516
R
F
P
A
H
K
M
N
B
J
Q
D
C
L
G
S
The installation shown in Fig. 1 is only a guide. For
assistance in designing a system to suit your needs,
contact your Graco distributor .
Mount the pump to suit the type of installation planned.
See page 22 for
Accessories.
Maximum W orking Pressure of Accessories
T o reduce the risk of serious bodily injury including
fluid injection and splashing in the eyes or on the
skin, which may be caused if a component rup -
tures, all accessories added to the reciprocator
power supply side must have at least a 1500 psi
(10 MPa, 103 bar) maximum working pressure and
those to the pump fluid outlet side must have at
least a 375 psi (2.6 MPa, 26 bar) maximum
working pressure.
WARNING

6 308-390
Installation
Pump Accessories
Suction T ube Kit
A suction tube kit is available for siphoning from 55
gallon containers.
Intake T ube (not shown)
T o install, apply tape to the female threads at
the top of the tube. Screw the tube tightly onto the
intake housing of the stubby pump.
Low-level Cutoff V alve
T o install, screw the low-level cutoff valve into the
bottom of the pump intake tube or the suction tube.
This valve closes the pump intake when the fluid level
is low , causing the pump to stall to avoid running dry .
Ground W ire
A ground wire is required. See Accessories , page 22.
Pump Outlet Drain V alve
Install a drain valve (D) close to the pump fluid outlet to
assist in relieving fluid pressure in the pump when the
pump
is shut of f. See warning below .
Pump Outlet Drain V alve
A pump outlet drain valve (D) is required in your
system. This valve helps relieve pressure in the
displacement pump and hose when shutting down
the system and in case of a clogged outlet hose.
Install the valve close to the pump outlet.
WARNING
CAUTION
Keep The Hydraulic System Clean
The hydraulic supply system must be kept clean
at all times to reduce the risk of damaging the
reciprocator hydraulic power supply . Blow out all
hydraulic lines with air, flush thoroughly with sol -
vent, and then blow out with air again before con -
necting the lines to the reciprocator .
Always plug the hydraulic inlets, outlets and lines
when disconnecting them for any reason to avoid
introducing dirt and other contaminants into the
system.
Carefully follow the manufacturer ’ s recommenda -
tions on reservoir and filter cleaning, and periodic
changes of hydraulic fluid.
Hydraulic Power Supply
To reduce the risk of overpressurizing the hydraulic
reciprocator , which could cause a rupture and
serious bodily injury , including fluid injection, the
hydraulic power supply must have a means to limit
the incoming fluid pressure developed in the sys -
tem to a maximum of 1500 psi (10 MPa, 103 bar) .
WARNING
PTFE

7308-390
Installation
Hydraulic Fluid Control
Always turn of f the hydraulic supply side valve (K
in Fig. 1) first to avoid possible serious injury or
component damage.
WARNING
The hydraulic fluid control provides pressure
regulation, flow regulation, and pump isolation. See
Fig. 1 for typical installation.
D Pressure Regulation
The hydraulic fluid control reduces the hydraulic oil
pressure to the operating pressure required for the
application.
D
Flow Regulation
The hydraulic fluid control limits the maximum
amount of oil flow to the motor to keep the hydraulic
motor within the recommended cycle rate limit. This
prevents pump runaway
. The limit on the Dyna-Star
is 60 cpm.
D Pump Isolation
The hydraulic fluid control has ball valves on the
supply and return sides of the manifold. The ball
valves isolate the hydraulic fluid control and pump
for servicing without stopping the hydraulic power
supply.
Grounding
T o reduce the risk of static sparking, ground the pump.
Check your local electrical code for detailed grounding
instructions for your area and type of equipment.
D Pump: Use ground wire and clamp as shown to the
right.
D
Hydraulic Hoses and Fluid Outlet Hoses: Use only
electrically conductive hoses.
D Hydraulic Power Supply and Air Compressor:
Follow manufacturer ’ s recommendations.
D Any pails used when flushing: Use only metal,
grounded pails when flushing. Make firm
metal-to-metal contact between the a metal part of
the dispense valve and the pail. Use the lowest
possible pressure.
To ground the pump, loosen the grounding lug
locknut (W) and washer (X). Insert one end of a 12 ga
(1.5 mm @ ) 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. See Fig. 2.
T o order a Grounding Wire and Clamp Kit, order Part
No. 222–01 1.
Fig. 2
ZX W
Y
03517

 
Operation
Pressure Relief Procedure
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 Install or clean the nozzle
WARNING
1. Close the supply line shut-of f valve (L in Fig. 1)
and the return line shut-of f valve (H). Shut of f the
hydraulic power supply .
2.
Open the dispensing valve to relieve pressure.
3. Open the pump outlet drain valve, and have a
container ready to catch the fluid.
4. Leave the drain valve open until you are ready to
spray again.
If you suspect that the nozzle or hose is completely
clogged, or that pressure has not been fully relieved
after following the steps above, very slowly loosen the
hose end coupling to relieve pressure. Now clear the
obstruction.
Be sure you always shut of f the hydraulic supply
line shutof f valve (K) first, and then the return line
shutof f valve. This is to prevent overpressurizing
the motor or its seals. When starting up the hy
-
draulic system, open the return line shutof f valve
first.
WARNING
Before Y ou Start The Pump
Recommended Hydraulic Oil
Use Graco-approved Hydraulic Oil or a premium,
ISO grade 46 petroleum-based hydraulic oil con -
taining rust and oxidation inhibitors and anti-wear
agents. See Accessories on page 22.
Before using any other type of oil in this motor ,
contact your Graco distributor . Unauthorized use of
lesser grade oil or substitutes may void the war -
ranty.
Hydraulic Oil W orking Temperature
The recommended hydraulic oil operating tempera -
ture is 80 to 1 15_ F (27 to 45 _ C). The motor
seals will wear faster and leakage may occur if the
pump is operated at higher oil temperatures.
If the hydraulic oil temperature approaches 130 _ F
(54_
C), check the hydraulic fluid supply cooling
system, filters, etc. and clean or repair as needed.
CAUTION
1. Check the hydraulic fluid level in the hydraulic
power supply before each use , and add fluid as
necessary to fill the lines.
2. Flush the pump before using it for the first time to
remove the light oil which was left in after factory
testing to protect the pump from corrosion. Be sure
the solvent used is compatible with the fluid to be
pumped and the pump wetted parts. See
T echnical Data on page 23. Flush until clean
solvent comes from the outlet hose.


Operation
Starting the Pump
Maximum W orking Pressures
T o reduce the risk of serious bodily injury includ-
ing fluid injection and splashing in the eyes or on
the skin, which may be caused if a component
ruptures:
Never exceed 1500 psi (10 MPa, 103 bar) Maxi -
mum Hydraulic Pressure to the reciprocator .
Never exceed 375 psi (2.6 MPa, 26 bar) Maxi -
mum Outlet Pressure from the displacement
pump.
Be sure all accessories added to the reciproca -
tor power supply side are capable of at least a
1500 psi (10 MPa, 103 bar) maximum working
pressure and all of those for the pump fluid out -
let side have at least a 375 psi (2.6 MPa, 26 bar)
maximum working pressure .
The maximum working pressure of the displace -
ment pump is directly proportional to the pres -
sure at which the reciprocator is operated.
Therefore, if the fluid supplied to the reciprocator
is 1000 psi (7 MPa, 69 bar), the pump fluid out -
let pressure will be 250 psi (1.7 Mpa, 17.4 bar).
WARNING
1. T urn on the hydraulic power supply .
2.
Open the return line shutoff valve (H) first and
slowly open the hydraulic supply line shutof f valve
(K).
3.
Adjust the hydraulic inlet pressure from 500 to
1500 psi (3.4 to 10 MPa, 34 to 103 bar) with the
pressure reducing valve control adjustment (M) on
the hydraulic fluid control (A). Increasing the inlet
pressure increases the outlet pressure.
Decreasing the inlet pressure decreases the outlet
pressure.
4.
Always use the lowest pressure possible to obtain
the desired results. This reduces pump wear .
NOTE:
Never allow a pump to run dry of the fluid
being pumped. A dry pump quickly speeds up and
can damage itself. If it speeds up, shut of
f the
power supply to the reciprocator immediately
. Refill
the supply container and prime the pump to
eliminate air . T o prevent the pump from running
dry , use a low-level cutof f valve.
If the Reciprocator Leaks at the Fluid
Fittings
Tighten the fittings (16, 17, 25), which are self-sealing
and have replaceable o-rings. If leaking persists,
change the o-rings. See Fig. 3.
Fig. 3
SELF-SEALING FIT -
TING (16, 17, 25)
O-RING
RECIPROCATOR
03522
Shutdown and Care
To stop the pump in an emergency , close the supply
line shutof f valve marked STOP.
The normal shutdown procedure is as follows:
1. Relieve the pressure.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 8.
2. Always shut of f the supply line shutoff valve (K)
first , and then the return line shutof f valve (H).
This is to prevent overpressurizing the reciprocator
or its seals.
NOTE: When starting the hydraulic system, open
the return line shutof f valve (H) first. See page 5.

10 308-390
Troubleshooting
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 8.
Note: Check all possible problems and solutions
before disassembling the pump or reciprocator .
PROBLEM CAUSE SOLUTION
Pump will not run. Closed dispense valve. Pump only runs with valve open.
Pressure too low .Increase supply pressure using the
pressure
adjusting valve.
Insuf ficient hydraulic fluid supply .Check hydraulic supply . Adjust to a
maximum
of 3 gpm (1 1 liter/min) flow .
Clogged fluid outlet line, intake
valve,
dispense valve, suction line.
Relieve pressure. Check; clear
obstructions.
Reciprocator damaged. Repair . See page 14 or 17.
Pump speeds up or runs erratically . Pump piston and/or intake
valve worn.
Relieve pressure. Check and repair .
See
page 18.
Empty supply container . Refill and reprime. Do not allow pump
to run dry . Monitor closely or use a low-
level cutof f valve.
Pump runs, but output low on up
and/or
down stroke.
Pump piston and/or intake valve
worn.
Relieve pressure. Check and repair .
See
page 18.
Pump runs but output low on both
strokes.
Insufficient hydraulic fluid supply . Check hydraulic supply .
Pressure too low .Increase supply pressure using the
pressure
adjustment on the control.
Clogged fluid outlet line, intake
valve,
dispense valve, suction line.
Relieve pressure. Check; clear
obstructions.
Excessive weepage from porous
plug
(B).
W orn throat seals.. Repair . See page 12.
Hydraulic oil leaks from fittings in the
upper or lower reciprocator blocks
(53, 47).
Fittings (16,17,25) are loose, or their
o-rings are worn or damaged.
Tighten the self-sealing fittings. If leak -
ing
persists, change the o-rings.

11308-390
Service
Replacing Base Packing in Reciprocator
See Fig. 4.
NOTE: Replace these seals if fluid leaks excessively
through the porous plug (107), see Fig. 5. This
procedure can be done without disassembling the
entire reciprocator .
1. Relieve the pressure.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 8.
2. Disconnect the reciprocator from the pump as
explained in the next section.
3. Remove the four capscrews (24) and washers (12)
from the bottom of the retainer housing (56). T ap
the retainer housing to loosen it and pull it of f the
bottom cap (47).
4. Remove the seal (22) and sleeve bearing (34)
from the top of the retainer housing (56).
NOTE: Item 22 is included in the Repair Kit,
236–861.
5. Lubricate the sleeve bearing (34) and install the
seal and sleeve bearing in the retainer housing
(56) in the order shown in Fig. 4 .
6. Reassemble. T orque the capscrews (24) to 28 to
32 ft-lb (43 to 43 N-m). Install the displacement
pump. Follow Step 22, page 17.
Fig. 4
47
56
34
Lips face UP 03523
1T
orque to 28 to 32 ft-lb (43 to 43 N-m)
1
2
222
12
24

12 308-390
Service
Disconnecting Reciprocator and Displacement Pump and Replacing Throat Seals.
See Fig. 5.
7, 6
Fig. 5
115
28
118
119
115
03520
116
105
103
107
117
110
During assembly, screw the
connecting rod (45 in Fig. 8)
into the piston rod (1 16) first.
2
2
06156
CAUTION
Keep The Hydraulic System Clean
It is essential to keep the hydraulic oil system
clean and free of contaminants to reduce the risk
of damaging the hydraulic reciprocator . Always
install a plug in each tube fitting and on each hose
end whenever fluid lines are disconnected to pre -
vent contamination.
1. Flush the pump if possible, and stop it with the
piston rod in the lowest position.
2. Relieve the pressure.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 8.
3. Disconnect the outlet hose from the displacement
pump.
4.
Slowly loosen the hydraulic hoses to the supply
(26) and return (25) fittings to relieve any pressure,
and then remove the hoses. Install plugs on the
tube fittings and in the hose ends. Check the o-ring
(13) on the fitting, and replace if worn or damaged.
See Fig. 4 and the Parts Drawing.
5. Using a strap wrench on the pump cylinder (1 18),
screw it out of the base (1 15) and remove it.
6. Place the piston (1 17) in a vise, and loosen the
piston rod (1 16).
7. Remove bolts (105) and washers (103).
CAUTION
Be careful not to scratch the outside of the piston
rod.
8.
Push the piston rod (1 16) up through the base
(1 15), and remove it.
9. Remove the throat seal (1 10). Apply fresh grease
to the new seal and groove. Install the new throat
seal.

13308-390
Service
Assembly after Replacing Throat Seals
See Fig. 5.
1. Apply fresh grease to the new throat seal (1 10)
and the mating groove in the base (1 15). Install
the new throat seal.
CAUTION
Be careful not to scratch the outside of the piston
rod.
2.
Push the piston rod (1 16) down through the base
(1 15), and install.
3. Install the bolts (105) and washers (103). T orque to
20 to 25 ft-lb (27 to 34 N-m).
4. Apply Loctite  242 to the threads on the piston
(1 17). Install the ball (104). Screw the piston into
the piston rod (1 16).
5. Place the piston (1 17) in a vise, and tighten the
piston rod (1 16). T orque to 155 to 175 ft-lb (210 to
237 N-m).
6. Apply fresh grease and install a new o-ring (1 12)
on the pump cylinder (1 18).
7. Using a strap wrench on the pump cylinder (1 18),
screw it tightly into the base (1 15).

14 308-390
Reciprocator Repair
NOTES:
DClean and inspect all parts for wear or damage.
Replace parts as needed. For the best results,
always replace all the o-rings and seals when you
disassemble the pump. Repair kit 236–861 is
available. Parts included in the kit are marked with
an asterisk on the parts lists.
D Assembly tool 189–305 is required for
reassembling the reciprocator . See Accessories to
order.
D For Step 9 and 10, Loctite r 242 thread sealant and
Loctite r Primer T OR Perma-Loc r 1 15 thread
sealant and Perma-Bond r surface conditioner are
required. Be sure their shelf life is within the
manufacturer’ s recommendations.
1. Loosen both nuts on the inlet tube (57). Use a
wrench to rotate the tube fittings (16, 17) to the
side, and then remove the tube (57). Install plugs
in the fittings to prevent contamination. See the
Parts Drawing
on page 20.
2. Remove the capscrew (14), nuts (7) and lock
washers (6) on top of the reciprocator . See Fig. 6.
Fig. 6
6, 7
47
14, 33, 27
03517
56
24
12
105
103
3.
Remove the four capscrews (24) and the retainer
housing (56). T ap the retainer housing with a
plastic mallet to loosen it and pull it of f the bottom
cap (47). See Fig. 6. If needed, replace the throat
seals as described on page 1 1.
See Fig. 9 for Steps 4 to 13, except where noted.
4. T ap on the bottom of displacement rod (54) with a
plastic mallet to loosen the motor cylinder (39).
5. Grasp the valve spool (31) and pull it of f the
cylinder and tie rods (49). Pull the cylinder and
piston of f the bottom cap (47). It is not necessary
to remove the tie rods from the cap.
6. Lay the assembly on its side. Place a clean rag
around the yoke ( 43) to prevent losing the detent
balls. Slide the yoke (43) sideways of f the valve
sleeve (32) while holding the balls (5) and spring
(20) in place.
7. Slide the cylinder (39) of f the displacement rod
(54). Hold the hex end of the displacement rod in a
vise and use a spanner wrench in the pin holes of
the piston (35) to screw it of f the rod.
CAUTION
Be careful not to scratch the outside of the dis -
placement rod.
8. V isually inspect the spring (36). If there is wear or
damage, proceed with this step. Remove the nut
(19), spring (36), and retainers (55) from the trip
rod (40). Reassemble with a retainer (55) on each
end of the new spring (36). Adjust the nut to obtain
the dimension shown in Fig. 7.
Fig. 7
55
36
19
55
1.580”
+/–
015”
03524
40

15308-390
Reciprocator Repair
06158
Fig. 8
40
49
6, 7
32
47
35
55
36
19
31a
13
5, 20
43
11
39
54
See Fig. 7
13
37
18, 38
14, 33, 27
52
45
1
2
Torque
to 30 to 40 ft-lb (41 to 54 N-m)
1
2
Apply
thread adhesive, and torque to 42 to 45
in-lb (4.7 to 5.1 N-m).
31
55
NOTES:
If any of these parts are being reused, use a
surface cleaner such as chlorinated solvent on the
threads and blow with compressed air . A #10–24
UNC–2B tap can be used to remove adhesive from
the internal threads of the yoke (43).
 Thread sealant and primer are required for Steps 9
and 10. See the third bulleted note on page 14 for
specifications.
9.
Apply three drops of fresh thread sealant to the
first two or three internal threads of the yoke (43).
Apply primer to the external thread of the rod (40).
Let dry for three or four minutes. Assemble, and
torque the rod to 54 to 56 in-lb (6.1 to 6.3 N.m).
Remove excess sealant. Allow 24 hours for the
primer to to cure before you operate the
reciprocator.
10. Normally the valve sleeve (32) and valve stop (44)
do not have to be replaced. However , if either part
must be replaced, first soak the parts in hot water
to loosen the sealant. Clean all sealant from the
threads of any part you are reusing and apply
three drops of thread sealant to the first two or
three internal threads of the valve stop (44). Apply
primer to the external thread of the valve sleeve
(32). Let dry for three or four minutes. Assemble.
Remove excess sealant. Allow 24 hours to cure
before operating the reciprocator .
11.
Use a spanner wrench to screw the piston (35)
onto the displacement rod (54). T orque to 30 to 40
ft-lb (41 to 54 N-m).
12. Install the o-ring (18*) in the deep lower groove of
the piston (35) and install the seal (38*) over the
o-ring. Install the piston bearing (37*) around the
upper groove of the piston. Holding the piston
bearing in place to avoid damage, slide the
cylinder over the piston and press it down.
When inserting the piston into the cylinder , care -
fully guide the piston seal (38*) and bearing (37*)
to prevent damaging these parts.
CAUTION

16 308-390
Reciprocator Repair
Fig. 9
53
upper detent holes
ASSEMBLY B
tool 189–305
44
20
5
43
32
40
ASSEMBLY A
03525
30
Slide curved ends
into groove of
valve sleeve (32)
13. See Fig. 9. Lay Assembly A and Assembly B on
the workbench.
14. Slide Assembly B into the the center of the tool.
Align the upper detent holes of the guide yoke (43)
with the center line of the tool. See Fig. 9.
15. Insert the spring (20) and one ball (5) into the
valve stop (44) of Assembly A. T ilt the valve stop
and start guiding it into the tool, making sure the
ball is sliding into the rounded slot in the tool.
Place the other ball at the other end of the spring
and push it in with your thumb while rotating the
valve stop (44) until the spring is horizontal and the
balls are in place. Continue holding this assembly
together . See Fig. 9.
16. Place your thumbs on the valve stop (44), grasp
the bottom of the tool with your other fingers and
press the assemblies together. Make sure the balls
(5) snap into the upper set of holes in the yoke
(43), and the curved ends of the guide clamp have
engaged the valve sleeve (32) groove. See Fig. 9.
Slide the tool back over the rod (40) to remove it.
Refer to Fig. 10 for Steps 18 to 24.
17. If the tie rods (49) were removed, reinstall them
with the short threaded end up. The other end
should be screwed about 9/16” into the bottom
cylinder cap (47).
NOTE: When reinstalling the cylinder (39) (Step 18),
be sure the “P” port in the valve spool (31) and the port
in the bottom cylinder cap (47) are in line with each
other . Be sure the o-rings (13) are in place in both
cylinder caps.
18. Slide the cylinder (39) with the piston/displacement
rod already installed in it, into the groove in the
bottom cylinder cap (47). Position the spool valve
(31) over the cylinder and press down firmly .
19. Install the capscrew (14), o-ring (33) and washer
(27). Install the lockwashers (6), nuts (7). T orque
the nuts to 28 to 32 ft-lb (36 to 43 N-m).

17308-390
Reciprocator Repair
Never install the fluid tube (57) before torquing the
tie rods. Doing so could cause misalignment and
damage the reciprocator when it is operated.
CAUTION
20. Reinstall the fluid tube (57) and fittings (17,16).
T orque the fittings to 25 to 35 ft-lb (34 to 48 N-m).
See the Parts Drawing on page 20.
21. Pull the displacement rod (54) in and out to be
sure it moves easily with only a little resistance
from the rod seal.
22. T o reconnect the reciprocator and pump, screw the
connecting rod (45) into the piston rod (1 16) and
torque to 75 to 85 ft-lb. Push the connected
assembly down through the base (115). Clean
piston (1 17) threads and apply Loctite  242.
Install ball (104). Screw piston (1 17) into piston rod
(1 16). Place assembly in a vise and torque to 155
to 175 ft-lb. Make sure the o-ring (1 12*) in the
outside groove of the pump cylinder (1 18) is in
good condition. Push the cylinder up into the
adapter and engage the threads. Screw in the
pump, using a strap wrench for the final tightening.
23. Connect the hydraulic supply hose to fitting (26)
and return hose to fitting (25).
WARNING
T o reduce the risk of static sparking be sure to re -
connect the ground wire before operating the
pump.
Fig. 10
Torque to 28 to 32
ft-lb (36 to 43 N.M)
118
110
115
03520
116
1
1
117
During assembly,
screw (45) into
(1
16) first.
2
206158
49
6, 7
47
13
39
13
14, 33, 27
52
45
31
56
54 22

18 308-390
Displacement Pump Repair
Intake V alve. See Fig. 11.
1. If possible, flush the pump.
2. Relieve the pressure.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 8.
3. Unscrew the valve body (1 19). Remove the o-ring
(108), ball (106), and retainer (120).
4.
Inspect the parts for wear or damage. If the ball is
nicked, replace it. Reassemble, using grease on
the male threads.
Displacement Pump. See Fig. 11.
NOTE: Clean and inspect all parts for wear or
damage as you disassemble them. Replace parts as
needed. For the best results, always replace all the
o-rings and packings when you disassemble the pump.
The parts list on page 19 gives the recommended
parts to keep on hand.
1. If possible, flush the pump.
2. Relieve the pressure.
WARNING
T o reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 8.
3. Follow Disconnecting the Reciprocator and
Displacement Pump on page 9. Remove the
intake valve.
4. Carefully inspect the smooth, inner surface of the
cylinder (1 18) for scoring or irregular surfaces.
Such damage causes premature seal wear and
leaking, so replace the part if needed.
5. Grease the new piston seal and install with the lips
facing up as shown in Fig. 1 1.
6.
Reconnect reciprocator and displacement pump
per steps 1 through 6 of Assembly after
Replacing Throat Seals
on page 13.
Fig. 11
115
116
104
112
117
120
106
108
119
03520
110
1
1
2
2
108
118
Lips face up.
Lips face down.

19308-390
Model 236–753 1/4:1 Ratio Pump Parts
Ref
No. Part No. Description Qty
Ref
No. Part No. Description Qty
101 236–751 RECIPROCATOR, Dyna-Star 1
see parts on page 20
103 100–133 WASHER, lock; 3/8 1
104 101–178*
BALL, metallic 1
105 102–637 SCREW
, cap hex hd; 3/8–16 x 1
1–1/2
106 108–001*
BALL, metallic, sst 1
107 110–064
PLUG, pipe, vented; 1/8–27 npt(f) 1
108 110–828* PACKING, o-ring 1
110 112–558* SEAL, block vee 1
111 112–565* SEAL, block vee 1
112 166–071* PACKING, o-ring 1
115 189–705
BASE, motor , hydraulic 1
116 189–706 ROD, piston 1
117 189–707 SEAT, valve 1
118 189–708 CYLINDER, pump 1
119 189–709 VAL
VE, housing 1
120 189–710 RET
AINER, ball 1
121 189–711 WASHER,
piston 1
* Included in Repair Kit 236–681. See Accessories on
page 22.
06159
121
120
119
118
117
111
112
110
103
105
104
108
116
106
101
03528
03529
115
107
During assembly,
screw the connect-
ing rod (45) into the
piston rod (1 16)
first.
1
1
45

 
Hydraulic Reciprocator Parts

MODEL 236–751, Series B
Hydraulic Reciprocator
Includes items 5 to 57
NOTE: See pages 1 1 to 17 for
important assembly
procedures and torque
values.
7
6
10
8
22
52
31a
49
37
36
20
9
32
25
27
43
57
14
33
31
17
26
16
44
13
13
39
40
35
18
38
11
54
19
11
55
55
45
47
34
56
12
24
5