OilGear A2 Series Operating instructions

THE OILGEAR COMPANY
905 South Downing Street
Fremont, NE 68025 USA
www.oilgear.com
Issued: May 2019
PUMP SERVICE MANUAL
Bulletin 948034A
Bulletin 948034A
Figure 1. Typical Oilgear “PVG” Open Loop Pump
PURPOSE OF INSTRUCTIONS
These instructionswillsimplifythe installation,
operation, maintenance andtroubleshooting of
Oilgear type “PVG” pumps.
Become familiar withthe construction, principl
eo
f
operation and characteristicsofyour pumpto help
youattainsatisfactory performance, reduce shut-
down and increasethe pump'sservice life.Some
pumps have been modified from those described in
this bulletin and other changesmay be made
without notice.
REFERENCE MATERIAL
Fluid Recommendations........................................................................................................................... Bulletin 90000
Contamination Evaluation Guide ............................................................................................................ Bulletin 90004
Filtration Recommendations..................................................................................................................... Bulletin 90007
Piping Information .................................................................................................................................... Bulletin 90011
Installation of Vertically Mounted Axial Piston Units................................................................................. Bulletin 90014
PVG Open Loop Pumps, Sales ............................................................................................................Bulletin 47019-K
Pump Control Instructions, Series A1
“P-1NN” Single Pressure Compensator ................................................................................................ Bulletin 948675
“P-1NN/F” Single Pressure Compensator w/Load Sense ..................................................................... Bulletin 948676
“P-1NN/H” Single Pressure Compensator w/H.P. Limiter ..................................................................... Bulletin 948677
“P-1NN/G” Horsepower Limiter w/Load Sense .................................................................................... Bulletin 948678
“P-1NN/K” Single Pressure w/Load Sense, Minimum Standby ............................................................ Bulletin 948683
“P-1NN/L” Single Pressure w/HP Limiter & Load Sense, Minimum Standby ....................................... Bulletin 948684
“P-2” Dual Pressure Compensator ...................................................................................................... Bulletin 948679
“P-C & P-K” Single Pressure - Soft Start ............................................................................................. Bulletin 948680
“P-CNN/H & P-KNN/H” Single Pressure - Soft Start w/H.P. Limiter...................................................... Bulletin 948681
“P-2NN/H” Dual Pressure Compensator w/H.P. Limiter........................................................................ Bulletin 948682
“P-E” Electronic Displacement Control ................................................................................................ Bulletin 948690
“P-E/F” Electronic Displacement Control w/Load Sense ..................................................................... Bulletin 948691
OILGEAR TYPE “PVG” PUMPS
180 (SERIES A2)
SERVICE INSTRUCTIONS

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
2
Bulletin 948034A
PUMP SERVICE MANUAL
Table of Contents
Safety First ..........................................................................................................................3 - 5
Preparation and Installation.................................................................................................6 - 7
Principle of Operation..........................................................................................................8 - 9
Specications .........................................................................................................................10
Troubleshooting...................................................................................................................... 11
Testing and Adjusting / Disassembly ..............................................................................12 - 13
Rotating Group / Inspection.............................................................................................14 - 16
Assembly.........................................................................................................................16 - 18
PVG Pump Torques Numbers & Descriptions........................................................................ 19
Parts List.................................................................................................................................20
O-Ring Seals Item Number List.............................................................................................. 21
Service Kits List...............................................................................................................22 - 23
Parts Exploded Views......................................................................................................24 - 27
Spare Parts Availability........................................................................................................... 28

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED 3
Bulletin 948034A
Bulletin 948034A
Safety First
PUMP SERVICE MANUAL
Read and understand this entire instruction sheet
be
fore repairing or adjusting your Oilgear product.
Those
who use and maintain this equipment must
be
thoroughly trained and familiar with the product.
If
incorrectly used or maintained, this product and
its equipment can cause se
vere injury.
SAFETY SYMBOLS
The
following signal words are used in this
inst
ruction sheet to identify areas of concern where
yo
ur safety may be involved. Carefully read the text
and
observe any instructions provided to ensure
yo
ur safety.
THIS SIGNAL WORD INDICATES AN
IMMINENTLY HAZARDOUS SITUATION
WHICH, IF NOT AVOIDED, WILL RESULT IN
DEATH OR SERIOUS INJURY.
This signal word indicates a potentially
hazardous situation which, if not avoided,
could result in death or serious injury.
This signal word indicates that a potentially
hazardous situation exists which, if not
avoided, may result in damage to
equipment or minor personal injury.
While not directly relevant to the topic being
discussed, the NOTE is used to emphasize
information provided, or provide additional
information which may be of benefit.
This service information is designed for
the maintenance of your Oilgear product.
It contains the information on the correct
procedures determined by Oilgear for the
safe manner of servicing. Always keep
this instruction sheet in a location where it
is readily available for the persons who
use and maintain the product. Additional
copies of this instruction sheet are
available through the Oilgear Company.
Or visit our website: www.oilgear.com.
Please contact us if you have any
questions regarding the information in
this instruction bulletin.
The cleanliness of working on this pump or
the hydraulic system is extremely
important to the safety and reliability of the
pump and the system. Always make sure
the fittings are clean on the outside before
removing them from their connections, are
capped and plugged when removed and
placed in a clean rag or container until they
are reinstalled.
Some service operations may require
special tools or equipment. If you require
information on these items, please contact
Oilgear before attempting these repairs
and service operations.
Read, understand, and follow the safety
guidelines, dangers, and warnings
contained in this instruction sheet to
promote reliable operation and prevent
serious personal injury.
DO NOT attempt to service this machinery
in an environment where safety regulations
are not established and in place.
DO NOT operate the hydraulic system if a
leak is present. Serious injury may result.
Hydraulic systems operate under very high
pressure. Hydraulic fluid escaping from a
pressurized system can penetrate
unprotected body tissue. DO NOT inspect
for hydraulic leaks with bare hands or other
exposed body parts. As a minimum, wear
leather gloves prior to inspecting for leaks
and use cardboard or wood. If leaks are
present, relieve pressure and allow system
to cool prior to servicing. If injured by
escaping hydraulic oil, contact a physician
immediately. Serious complications may
arise if not treated immediately. If you have
questions regarding inspecting for
hydraulic leaks, please contact Oilgear
prior to servicing.
DANGER
! !
!WARNING
CAUTION
NOTE
!WARNING
NOTE
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED
4
Safety First
Bulletin 948034A
Bulletin 948034A
PUMP SERVICE MANUAL
Hydraulic
hoses and tubing must be
inspected
on a daily basis for leaks, cuts,
abrasions,
damage and improper
cl
earance along any mounting frame for
hidden
damage before the unit is put into
servic
e. Replace damaged hoses or hoses
y
ou suspect are damaged before the
system is returned to service! Hoses m
ust
be
replaced every two years. Failure to
pr
operly inspect and maintain the system
ma
y result in serious injury.
Hydraulic
systems are hot. DO NOT
TO
UCH! Serious personal injury may
result
from hot oil. When you have
completed
working on the hydraulic
system,
thoroughly clean any spilled oil
fr
om the equipment. Do not spill any
hy
draulic fluids on the ground. Clean any
hy
draulic fluids from your skin as soon as
y
ou have completed maintenance and
repair
s. Dispose of used oil and system
filter
s as required by law.
Use
correct hoses, fittings, and adapters
with
the correct SAE rating when
replacing
hoses to prevent possible
serious
injury. Always replace hoses,
fittings,
and adapters with replacements
that
have a proper, suitable, working
pressure
rating. Replacement hoses must
be
of the correct length and must comply
with
the hose manufacturerʼs and
Oil
gearʼs installation guidelines and
recommendations.
Hydraulic
hoses have the SAE ratings
marked
on the hose to assist you in
selecting
the correct hose. The same
manufacturer
must supply any replacement
hy
draulic hoses and fitting assemblies. As
an e
xample: Brand “X” hose and brand “Y”
fitting
will not normally be compatible. No
“T
wist” is allowed in the hydraulic hoses.
“T
wist” may result in premature hose
failur
e. This can cause serious injury.
Please contact Oilgear
for assistance when
required.
Hydraulic cylinders can be holding
a
function in a certain position when the
pump is OFF. An example of this is
a
function being held in the lift or partial lift
position by the cylinders. If a hydraulic
line is removed or the hydraulic circuits or
controls are being worked on, gravity may
allow the function being held in position to
drop. All workers and personnel must
remain clear of these areas when working
on or operating the hydraulic system.
Block and secure all devices and
functions which apply before beginning
work or operation. Failure to comply with
this can result in serious injury or death.
Any hydraulic pipe which is replaced must
conform to SAE J1065 specifications. If
incorrect hydraulic pipe is installed, the
hydraulic system may fail, causing
serious injury. Damaged or leaking
fittings, pipes or hoses must be replaced
before the system is returned to service.
DO NOT heat hydraulic pipe. The carbon
content of this steel tube is such that if
heated for bending, and either water or air
quenched, the pipe may lose its ductility
and thereby be subject to failure under
high pressure conditions. Serious injury
can result. Damaged or leaking pipes must
be replaced before the system is returned
to service. Please contact Oilgear if you
require assistance or have questions.
All hydraulic pressure must be reliev
ed
from the hydraulic system prior to remo
ving
any components from the system. To
relieve the hydraulic pressure from t
he
hydraulic system, turn off the motor and
operate the control panel with the key in the
ON position. Failure to comply can result in
serious injury. If you have any questions
concerning relieving the h
ydraulic pressure
from the system, please contact Oilgear.
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED 5
Bulletin 948034A
Bulletin 948034A
Safety First
PUMP SERVICE MANUAL
Hydraulic
components can be heavy. Use
caution
while lifting these components.
Serious
personal injury can be avoided
with pr
oper handling of the components.
Please
contact Oilgear if you require
assistance,
when performing hydraulic
test
procedures, use the proper hydraulic
gauges.
Installing an incorrect test gauge
could
result in serious injury if the gauge
fails.
Use properly rated hydraulic hoses
to
allow the test gauge to be read away
fr
om moving parts and functions.
Increasing
hydraulic pressure beyond the
recommendations
may result in serious
dama
ge to the pump and system or
serious
personal injury and may void the
Oil
gear Warranty. If you have questions
concerning
hydraulic pressures or testing
pr
ocedures, please contact Oilgear before
attempting
the test procedures or making
adjustments
.
An
Oilgear pump must not be modified in
an
y way without authorization from
Oil
gear. Modifications may not comply
with
safety standards, including ANSI
saf
ety standards, and may result in
serious
personal injury. Please contact
Oil
gear if you require assistance.
DO
NOT enter under hydraulic supported
equipment
unless they are fully supported
or
blocked. Failure to follow this procedure
can result in serious injury or death.
Any Oilgear pump safety decals must be
replaced anytime they are damaged,
missing, or cannot be read clearly. Failure
to have proper decals in place can result
in serious injury or death. (If you require
safety decals, please contact Oilgear for
replacement safety decals, at no charge.)
Be sure everyone is clear of the area
around the hydraulic system before
operating after servicing. Remain attentive
at all times when operating to check your
work until you are completely sure it is
safe to return to service. Failure to heed
this warning may result in serious
personal injury or death.
Wear the proper protective clothing when
operating, servicing or maintaining the
hydraulic system or the Oilgear pump. Wear
the correct protective gear, safety glasses,
gloves, and safety shoes. Serious injur
y
can result without proper protective gear.
Make sure to keep hands and feet and
other parts of your body clear of revolving
or moving parts. Failure to comply can
cause serious injury.
DO NOT wear watches, rings, or jewelry
while working with electrical and
mechanical equipment. These items can
be hazardous and can cause serious and
painful injuries if they come into contact
with electrical wires, moving parts, or
hydraulic equipment.
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING
!WARNING

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
6
Bulletin 948034A
PUMP SERVICE MANUAL
PREPARATION AND
INSTALLATIO
N
MOUNTIN
G
Pump
Without Reservoir - The pump can be
mounted
in any position. But, the recommended
mounting
position is with the drive shaft on a
ho
rizontal plane and the case drain port 1 on the
top
side. Secure the pump to a rigid mounting
surf
ace. Refer to the referenced Oilgear Piping
In
formation Bulletin 90011.
Pump
With Reservoir - These pumps are usually
fully
piped and equipped. It may be necessary to
connect
to a super-charge circuit when used.
Mount
reservoir on level foundation with the
rese
rvoir bottom at least six inches above floor
le
vel to facilitate fluid changes.
PIPING AND FITTING
S
Re
fer to the referenced Oilgear Piping Information
Bulletin 90011 and individual circuit diagr
am before
connecting
the pump to the system. Inlet velocity
mu
st not exceed 5 fps (1,5 mps). Inlet should be
unrestricted and ha
ve a minimum of fittings.
DO NOT use an inlet strainer.
A
rrange line from “case drain” so the case remains
full of fluid (non-siphoning).
Case pressure must be
less
than 25 psi (1,7 bar). For higher case
pressure
s, special shaft seals are required; contact
our
Customer Service. Each drain line must be a
separate
line, unrestricted, full sized and
connected
directly to the reservoir below the lowest
fluid
level. Make provisions for opening this line
without draining (siphoning) reser
voir.
Running the pump in NEUTRAL position
(zero delivery) for extended periods
without a supercharge circuit can damage
the pump. The system and pump must be
protected against overloads by separate
high pressure relief valves. Install bleed
valve(s) at the highest point(s) in system.
POWER
Power is required in proportion to volume and
pressure used. Motor size recommendations for
specific applications can be obtained from The
Oilgear Company. Standard low starting torque
motors are suitable for most applications.
DO NOT start or stop unit under load
unless system is approved by Oilgear. It
may be necessary to provide delivery
bypass in some circuits.
DRIVE
Verify rotation direction plate on the pump's housing
.
Clockwise pumps must be driven clockwise an
d
counterclockwise pumps must be driv
en
counterclockwise. Use direct drive coupling. Size
and install coupling per manufacturer's instructions.
DO NOT drive the coupling onto the pump
drive shaft. If it is too tight, it may be
necessary to heat coupling for installation.
Refer to manufacturer's instructions.
Misalignment of pump shaft to driver's shaft should
not exceed 0.005 inches (0,13 mm) To tal Indicator
Readout (TIR) in any plane.
NOTE
!WARNING
CAUTION
CAUTION

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED
Bulletin 948034A 7
Bulletin 948034A
PUMP SERVICE MANUAL
Ke
ep the fluid clean at all times to ensure long life
from
your hydraulic system. Refer to the referenced
Oilgear
Filtration Recommendations bulletin 90007
and
Oilgear Contamination Evaluation Guide
Bulletin
90004. Oilgear recommends use of a filter
in
the pressure or return line. Replace filter
element(s)
when the filter condition indicator
reaches
change area at normal fluid temperature.
Drain
and thoroughly clean filter case. Use
replacement
element(s) of same beta 10 ratio
(nor
mally a ratio of 4 with hydraulic oils).
FLUID COOLIN
G
FILTRATION
When
the pump is operated continuously at the
ra
ted pressure or frequently at peak load, auxiliary
cooling
of the fluid may be necessary. Fluid
temper
ature should not exceed limits specified in
the
referenced Oilgear Fluid Recommendations
Bulletin 90000
.
AIR BREATHER
On
most installations, an air breather is mounted
on
top of fluid reservoir. It is important for the
breather to be the adequate si
ze to allow air flow in
and
out of reservoir as fluid level changes. Keep
the
breather case filled to the “fluid level” mark.
A
bout once every six months, remove cover, wash
screen
in solvent and allow screen to dry, clean
and
refill case to level mark and install screen.
Re
fer to the manufacturer's recommendations.
FLUID, FILLING AND STAR
TING
RECOMMENDATION
S
Re
fer to instruction plate on the unit, reservoir,
machine
and/or reference, Fluid Recommendations
bu
lletin. Fire resistant fluids and phosphate ester
fluids
can be used in accordance with fluid
manu
facturer's recommendations.
1.
Pump all fluid into reservoir through a clean
(beta 10 ratio of 4 or more) filter. Fill reservoir
to, but not above, “high level” mark on the sight
gauge.
2.
Remove case drain line and fill pump case
with hydraulic fluid.
3.
Tu rn drive shaft a few times by hand with a
spanner wrench to make sure parts rotate.
To rque to turn drive shaft should be 9 to 24 ft•lb
(12 to 32 N•m).
With pump under “no load” or with pump control at
NEUTRAL:
4. Tu rn drive unit ON and OFF several times
before allowing pump to reach full speed. The
system can usually be filled by running the
pump and operating the control.
5. The fluid level in the reservoir should decrease.
Stop the pump. DO NOT allow the fluid level to
go beyond the “low level.” If the level reaches
“low level” mark, add fluid and repeat step.
With differential (cylinder) systems, the fluid
must not be above “high level” when the
ram is retracted or below “low level” when
extended. Bleed air from the system by
loosening connections or opening petcocks
at the highest point in the system. Close
connections or petcocks tightly when solid
stream of fluid appears.
CONSTRUCTION
SeeFigure 3.
A drive shaft (301) runs through the center line
of pump housing (001)and valveplate (401)
with the pump cylinderbarrel (101) splined to it.
A bearing (306) supports the outboard end of
the drive shaft and a bushing supports the
inboard end. (The bushingis part of valveplate
assembly.)
The pump cylinder barrel is carried in a
polymerous (journal type)
bearing (001).
The valve plate (401)has two crescent shaped
ports.
The pumping piston/shoe assemblies (102)in
the cylinder barrel are held against a
swashblock (201) by a shoe retainer (104).
The shoe retainer is held in position by the
fulcrum ball (103) which is forced outward by
theshoe retainer spring (105).
The spring acts againstthe pump cylinder
barrel, forcing it against the valve plate
while
also forcingthe piston shoes against the
swashblock.
The semi-cylindrical shaped swashblock limit
s
the piston stroke and can be swiveled in arc
shaped saddle bearings (204).
The swashblockisswiveled by a contro
l
(included in referenced material). Refe
rt
o
PRINCIPLE OF OPERATION
.
NOTE

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
8
Bulletin 948034A
PUMP SERVICE MANUAL
PRINCIPLE OF OPERATION
The illustrations show the pump driven counter-
clockwise (left hand) from the top (plan) view.
Figure 2. Cut-away of a
Typical “PVG” Pump
PositionB, Pump During Full Delivery From
PORT B - Figure 3
Rotating the drive shaft (301) counter-clockwise
turns the splined cylinder, whichcontainsthe
pumping pistons(102).When the cylinderrotates,
thepistons move in and out within their bores as
the shoes ride against the angled (C) swashblock
(201).
As the cylinder rotates, the individual piston bores
are connected, alternately, to the crescent shaped
port A and port Bin the valve plate. While
connected to the suction port A, each piston moves
outward (OUT), drawing fluid from port Ainto the
piston bore until its outermost stroke (D) is
reached. At this point, the piston bore passes from
port Ato port B.
While rotating across the crescent port B, each
piston moves across the angled swashblock face
and then each piston is forced inward (IN). Each
piston then displaces fluid through the crescent to
portBuntil its innermost stroke (D) is reached. At
this point, the piston bore passes from the B to the
Acrescent again and the cycle is repeated.
Figure 3. Position B, Pump During Full Delivery From Port B
A
A
C
IN
OUT
AB
301
306
001 201
103
104 102
101 401
DSECTION A-A

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED
Bulletin 948034A 9
Bulletin 948034A
PUMP SERVICE MANUAL
Position B/2, Pump During One Half Delivery
From PORT B - Figure 4
This illustration shows that the angle (E) of the
swashblock determines the length of the piston
stroke (F), (the difference between outermost and
innermost position) which determines the amount
of delivery from the pump. In this case, the stroke
angle (E) is one-half of the stroke, which means the
piston stroke is one-half and the pump delivery is
one-half.
Position N, Pump In Neutral, No Stroke, No
Delivery - Figure 5
Neutral position results when the control
centers the swashblock. The swashblock
angle (G) is now zero and swashblock face is
parallel to the cylinder face. There is no
inward or outward motion of the pump pistons
as piston shoes rotate around the swashblock
face. With no inward and outward motion or
no stroke (H),NEUTRALno fluid is being
displaced from the piston bores to the
crescents in the valve plate and there is no
delivery from pump ports.
Illustration reference numbers match
thepart item number in the parts list.
Figure 4. Position B/2, Pump During One Half Delivery From Port B
Figure 5. Position N, Pump In Neutral, No Stroke, No Delivery
Refer to SPECIFICATIONS
NOTE
A
A
EF
IN
OUT
AB
SECTION A-A
A
A
G
AB
NEUTRAL
NEUTRAL
HSECTION A-A

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
10
Bulletin 948034A
PUMP SERVICE MANUAL
SPECIFICATIONS
Refer to reference material, pump control
material and individual application circuit
for exceptions.
Case pressure should be less than 25 psi (1,7 bar). For higher case pressure, consult factory.
Table 1. Nominal Performance Data with 150-300 SSU viscosity fluids.
All dimensions (without controls) are approximate. For detailed dimensions, contact
your Oilgear Representative.
Table 2. Nominal Dimensions without controls.
Refer to installation drawings for more detailed dimensions and port configurations.
NOTE
Unit
THEORETICAL
MAXIMUM
DISPLACEMENT
RATED
CONTINUOUS
PRESSURE
PEAK
PRESSURE
FLOW RATE at
1800 rpm rated
continuous pressure
and 14,7 psia (bar abs)
inlet condition
MAXIMUM
SPEED
POWER
INPUT at rated
continuous
pressure &
1800 rpm
in 3/revml/revpsi bar psibar gpml/mirpm hp kw
PVG 180 11.00 180,0 5000 344,8 5800 400,078.0 295,32400 260193,9
Unit LengthWidth Height Weight Face Mounting
inches mm inches mm inches mm lbs.kg
PVG 18015.1 383,3 8.4 213,48.9 226,1197*90SAE “D” 4 bolt
* Weight with "P-1NN" Control and thru shaft valve plate
.

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED
Bulletin 948034A 11
Bulletin 948034A
PUMP SERVICE MANUAL
TROUBLESHOOTING
PROBLEM CAUSES REMEDY
Unresponsive or
Sluggish ControlSwashblock saddle bearings (204) worn or damaged. Refer to referenced control instruction material.
Inspect bearings. Replace.
Insufficient Pump
Volume
.lairetamnoitcurtsnilortnocetairporppaotrefeRlortnocytluafybdetimilyrevileD
Obstructed suction circuit or insufficient supercharge volume.Inspect for obstruction and verify supercharge.
.lairetamrewopetairporppaotrefeR.deepsrotomevirdtneiciffusnI
Worn or grooved cylinder barrel (101) and/or valve plate (401)
mating surfaces.
Inspect components. Replace.Worn piston/shoe assemblies (102) or piston bores in cylinder
(101).
Worn or damaged piston shoe or swashblock (201).
Irregular or
Unsteady Operation
Faulty control. Inspect components. Replace. Refer to referenced
pump control instruction materials.
Fluid level in reservoir is low or supercharge is insufficient. Verify fluid level and/or supercharge.
Air entering hydraulic system .kaelrofmetsystcepsnI.
.ecalpeR.stnenopmoctcepsnI.pmupnotsiplaixanroW
Faulty output circuit components (cylinder, motors, valves or
other related components). Inspect components. Replace.
Loss of Pressure
Worn piston pump.
Inspect components. Replace.
Worn or grooved cylinder barrel (101) and/or valve plate (401)
mating surfaces.
Worn piston/shoe assemblies (102) or piston bores in cylinder.
Faulty output circuit components.
Excessive or High
Peak Pressure .sevlavfeil
erehtkcehC.stnenopmoctiucrictuptuoytluaF
Excessive Noise
Pump stopped or started incorrectly under load. Verify operation procedure of pump.
Low fluid level in reservoir or insufficient supercharge causing
cavitation.Verify fluid level and/or supercharge.
Air entering hydraulic system .kaelrofmetsystcepsnI.
Fluid too cold or viscosity too high. Verify fluid temperature and/or type.
Suction line problem i.e.; obstructions in line, line too long, line
diameter too small or too many bends and/or loops in line. Inspect line for obstruction.
Broken or worn piston/shoe assembly (102).Inspect components. Replace.
.pmupfonoitceridnoitarepotcepsnI.noitceridgnorwnignitatorpmuP
Excessive Heating
Operating pump above rated or peak pressure.Verify pump limitations.
Low fluid level in reservoir or insufficient supercharge.Verify fluid level and/or supercharge.
Air entering hydraulic system.Inspect system for leak.
Worn piston pump.
Inspect components. Replace.
Worn or grooved cylinder barrel (101) and/or valve plate (401)
mating surfaces.
Faulty output circuit components (continuous blowing relief valves
or "slip" through valves, cylinder or other components.
Insufficient cooling provision or clogged coolers. Inspect for obstruction.

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
12
Bulletin 948034A
PUMP SERVICE MANUAL
TESTING AND ADJUSTING
Shut the pump OFF and release pressure
from the system before disassembling
components. Failure to comply with these
instructions could result in personal injury
or death. Blocking the pressure line
between the pump and the system (or
pump) high pressure relief valve will result
in damage and could result in serious
personal injury.
PISTON PUMP
To
check for a worn piston pump, make a leak
measurement
test from the case drain while the
pump
is under pressure. After the unit is warm,
either
install a flow meter in the drain line or have
the
flow from the drain line directed into a large
container
or reservoir. The pump case must remain
full of fluid during this test
.
DO NOT run a pump on stroke against a
blocked output unless it is protected by a
high pressure relief valve and then run no
longer than necessary to check slip. Limit
discharge to prevent dropping reservoir
fluid below low level.
With
an accurate high pressure gauge in the
pressure
line, start the pump and stall (or block)
output
device to raise system pressure to
maximum
(as set by system relief valve). Read the
measurement
on the flow meter or time and
measure
the case drain flow to fill a known size
container and calculate the fl
ow rate.
Additional leakage indicates wear, but
does not become critical until it impairs
performance.
DISASSEMBLY
The cleanliness of working on this pump or
the hydraulic system is extremely important
to the safety and reliability of the pump and
the system.
When disassembling or assembling the
pump, choose a clean, dry, dust and sand
free area where no traces of abrasive
particles are in the air which can damage
the pump and system. DO NOT work near
welding, sandblasting, grinding benches or
similar conditions.
Always make sure the fittings are clean on
the outside before removing them from
their connections. Make sure they are
capped and plugged when removed. Place
them on a clean surface and in a clean rag
or container until they are reinstalled.
When cleaning parts which have been
disassembled, it is important to use
CLEAN cleaning solvents and parts are
allowed to dry. All tools and gauges should
be clean prior to working with the system
and use new, CLEAN lint free rags to
handle and dry parts.
DO NOT attempt to remove or install any
components or assembly while the pump
and system is running. Always stop the
pump, shut OFF the power and release
pressure from the system before servicing
or testing. Be sure provisions have been
made so the case drain line can be
disconnected from the unit without
causing the line to drain (siphon) the
reservoir.
(continued)
!WARNING
CAUTION
NOTE
NOTE
!WARNING

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED
Bulletin 948034A 13
Bulletin 948034A
PUMP SERVICE MANUAL
DISASSEMBLY (Continued)
Disconnectcase drain line from port 1or 1A.
Drain pump case through the remaining (port 1
or 1A) on the bottomofcase. If plugs are
inaccessible, it may be necessary to remove
the pump from themounting anddrive motor
before draining it.
After removing the pump from themounting
and before disassembly,cap or plug all ports
andclean the outside of unit thoroughly to
prevent dust from entering the system. See
Figures 12 and1.
Depending on what part or parts are to be
inspected, it may not be necessary to
completely take apart all assemblies.
CONTROL GROUP
Refer to the reference material for the information
which applies to the control your pump is equipped
with. Some force is required to remove the control
housing.
Remove socket head cap screws.
Lift the control group assembly, with control pin,
(721) straight up from the top of the pump
assembly. Thecontrol pin may or may not
remain in the swashblock (201).
Remove control O-rings (1228) (1015)
from the pump housing.
VALVE PLATE GROUP
If another pump is coupled to thru-shaft pumps,
it
will be necessary to remove coupling (501
)
before removing valve plate. Figures 14
15
1. Block the pump on a bench with the drive shaft
facing down.
2. Remove the valve plate (401) by removing four
socket head cap screws (403) and lifting it
straight up.
3. Remove valve plate O-ring
(1013)
and
(1261)
.
NOTE

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
14
Bulletin 948034A
PUMP SERVICE MANUAL
ROTATING GROUP
The rotating group is heavy. Be careful not
to damage cylinder wear surface which
mates against the valve plate, bearing
diameters or piston shoes. Use proper
lifting techniques and assistance from
others to prevent personal injury.
1.
Place the pump in a horizontal position.
2.
Remove the rotating group slowly by pulling the
cylinder barrel (101)from the housing.
3.
Identify (number) each pump piston shoe
assembly (102)and its respective bore in the
cylinder barrel (101) and shoe retainer (104) for
easy reassembly.
4.
See Figure 6. Lift out shoe retainer (104)with
pistons (102)and remove the fulcrum ball (103)
and shoe retainer springs (105).
INSPECTION
Clean all parts thoroughly and allow them to dry.
Inspect all seals and O-rings for hardening,
cracking or deterioration. Replace if necessary or if
you suspect damage. Check all locating pins for
damage and springs for cracking or signs of wear.
Wear proper protective gear when using
solvents or compressed air, servicing or
maintaining the hydraulic system or the
Oilgear pump. Wear correct protective
gear, safety glasses, gloves, and safety
shoes. Serious injury can result without
proper protective gear.
CONTROL GROUP
Refer to the reference material on pump controls.
Be sure to carefully check the control pin for cracks
and/or signs of fatigue. Check fit of the pin in the
swashblock. It should be a slip-fit without side-play.
Replace if necessary or if you suspect damage.
!WARNING
101
103
105
104
102
!WARNING
Figure 6. Rotating Group Disassembly
DRIVE SHAFT GROUP
1. Remove the drive key (303), if used and the
drive shaft bearing retainer ring (305).
2. Grasp outboard end of drive shaft (301)and
pull it out of the pump housing.
3. Remove the shaft seal retainer (302).
Reach inside the case and remove the
VALVE PLATE GROUP
Inspect the valveplate (401)surface which mates
with the cylinder barrel (101)for excessive wear.
Remove minor defects by lightly stoning the
surface with a hard stone which is flat to within
0.001 inches (0,03 mm).
Be sure to stone lightly. Any excessive
stoning will remove the hardened surface.
If wear or damage is extensive, replace the
valve plate.
NOTE
1. Remove screws (225)
2.
Place pump in vertical position with valve plate
down.

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED
Bulletin 948034A 15
Bulletin 948034A
PUMP SERVICE MANUAL
See Figure7.Checkeachshoe face fornicks and
scratches,and theshoefor smoothpivot action on
the piston.
If oneormorepiston/shoe assembly needs
to be replaced,replace allthe piston/shoe
assemblies.Wheninstallingnew piston/
shoe assemblies or therotatinggroup,
make sure thepistons move freely in their
respective bores.
Figure7.Pistonand Shoe Inspection
SWASHBLOCK GROUP
Inspec
t
theswashblock (201) forwear.Ifdefects ar
e
minor,stone theswashblock lightly.If damage
is
extensive, replace the swashblock.
Checkthe small holes in thefaceoft
he
swashblock. The holes provide“porting” fort
he
hydrostatic balancefluid of thep
iston/shoe
assembly to be channeled throughthe swashbloc
k
to thefaceofthe saddle bearing, providin
g
pressure lubrication.
Checkthe mating surfaceofswashblockfor
cracks
or excessive wear.The swashblockmovement in
thesaddlebearingsmustbesmooth.
Be sure to stone lightly.Any excessive
stoning will remove thehardenedsurface.
If wear or damage is extensiveand defects
cannot be removed, replaceifnecessary
or if yoususpect them of beingbad.
NOTE
B
A
OILG-0005
NOTE
NOTE
Allshoes must be equal within0.002 inches
(0,025 mm) at this dimension.
All shoe faces must be free of nicks.
End play should not exceed 0.002inches
(0,076 mm) when newor0.006 inches
(0,152 mm) when worn.
Figure Hydrodynamic Bearing removal
RO
TATING GROUP
Inspect
cylinder barrel (101)pistonbores and the
fa
ce whichmatewiththe valveplatefor wear.
Remo
ve minor defectsonthe face by lightly
stoning or lapping the surface.
Chec
kall piston and shoe assemblies (102)to
be
sure they ride properlyonthe swashblock.
Be sure to stone lightly. Anyexcessive
stoning will remove thehardenedsurface.
If wear or damageisextensive anddefects
cannot be removed, replacethe cylinder
barrel.
NOTE

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
16
Bulletin 948034A
PUMP SERVICE MANUAL
DRIVE SHAFT GROUP
Chec
k:
•the shaft bearing (306)for galling, pitting,
binding or roughness.
•the rear shaft bushing in valve plate.
•the shaft and its splines for wear. Replace
any partsnecessary.
1. Press shaft seal (007) into the saddle (216).
2. Align hole in bottom of saddle (216)with pi
n
(217) in housing. Install saddle in housing an
d
fasten with eight (8) screws (225).
3. Place housing on a bench with the
mounting
flange side down.
4. Grease the back side of each saddle bearin
g
(204A and204B) and install on the appropriat
e
side of the saddle (216).
5. The swashblock is inserted from the valve plat
e
end. Insert swashblock (201) into the pum
p
housing. Once in place, be sure the swashbloc
k
swivels in the saddle bearings. With ne
w
bearings, swiveling may be stiff and not alwa
ys
smooth.
If removed,
ASSEMBLY
Se
eFigures and . Follow the disassembly
procedures
in reverse for re-assembling the pump.
Durin
gassembly, install new seals and O-rings.
A
pplyathin film of CLEAN greaseorhydraulic
fluid to
sealing components to ease assembly. If a
new
rotating group is used, lubricate thoroughly
with
CLEAN hydraulic fluid. Apply fluid generously
to
all wear surfaces.
Hydrodynamic Bearing
If the hydrodynamic bearing was removed, a new
one will need to be pressed into the pump housing.
A special tool is required in order to press the
bearing in correctly, See Figure 9. From the valve
plate end, place the new bearing into the pump
housing. Adjacent to where the bearing will be
pressed is a slightly larger bore, with a lead-in
chamfer, see Figure 11. In preparation for pressing,
insert the bearing into this bore and verify it sits
flush. Orient the bearing so that the split in the
bearing is located 90 degrees clockwise from the
control mounting face, See Figure 10. Insert the
small diameter end of the pressing tool inside the
pump housing and into the bearing. Press the
bearing until the tool becomes flush with the valve
plate mounting surface.

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED
Bulletin 948034A 17
Bulletin 948034A
PUMP SERVICE MANUAL
.
I10. Hydrodynamic Bearing Seam Orientation
11. Hydrodynamic Bearing Installation

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
18
Bulletin 948034A
PUMP SERVICE MANUAL
The rotating group weight is heavy. Be
careful not to damage cylinder wear
surface which mates against the valve
plate, bearing diameters or piston shoes.
Use proper lifting techniques and
assistance from others to prevent
personal injury.
The rotating group can now be carefully installed
over the end of the drive shaft (301) and into the
pump housing (001).
When installing the rotating group, support
the weight of the cylinder barrel (101), as
cylinder spline is passed over the tailshaft,
to avoid scratching or damage.
4. Push cylinder forward until the cylinder spline
reaches the drive shaft spline and rotate
slightly to engage shaft splines. Continue to
slide cylinderforward until it encounters the
bearing Continue pushing the
cylinder forward until the piston shoes
contactthe swashblock. The back of the
cylinder should protrude approximately 0.25
inches (6 mm) from the back of the pump
housing.
VALVE PLATE GROUP
1. Place the pump housing on a bench with the
open end facing up.
2. Installnew O-rings (1013)and(1261)on the
housing.
3. Assemble the valve plate(401)onto the
housing(001) making sure the screw holesare
aligned.
4. Hand-tighten the socket head cap screw
(403) closest to O-ring (1013) first, then
alternately tighten the other cap screws.
On
thru-shaft unitsconnected to anotherpump
or device, install coupling (501).
Refer to PREPARATION andINSTALLATION
when pump is ready to be returned to service.
!
WARNING
NOTE
DRIVE SHAFT GR
OUP
1.
Place the housing on its side with the axis
horizontal.
2.
Install the seal retainer (302).
3.
Lubricate the shaft seal (007) and shaft.
4.
Insert the drive shaft (301) and bearing
assembly into the housing.
5.
Lock in place with the drive shaft bearing
retainer ring (305).
RO
TATING GROUP
Se
eFigure 6.
1.
Place the cylinder barrel (101), wear surface
down, on a clean cloth.
2.
Place the nine (9) shoe retainer springs (105)
in the spring pockets of the barrel with the
fulcrum ball (103) on top of it.
3.
Insert the identified pistons (102) into their
corresponding identified holes of the shoe
retainer (104). As a unit, fit the pistons into their
corresponding, identified bores in the cylinder
barrel. DO NOT FORCE. When parts are
aligned properly, the pistons will fit smoothly.

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED
Bulletin 948034A 19
Bulletin 948034A
PUMP SERVICE MANUAL
Table 3. PVG Pump Torques
Fastener or Plug
Item Number Description Head Type
& Size
Tightening
Torque
225
3.25
1.23

© 2019 THE OILGEAR COMPANY - ALL RIGHTS RESERVED Bulletin 948034A
20
Bulletin 948034A
PUMP SERVICE MANUAL
PARTS LIST
Parts used in these assemblies are per Oilgear
specifications. Use only Oilgear parts to ensure
compatibility with assembly requirements. When
ordering replacement parts, be sure to include
pump type and serial number, bulletin number and
item number. Specify type of hydraulic fluid to
assure seal and packing compatibility.
Parts drawings may not be identical to
Oilgear drawings referenced.
PARTS LIST drawings on pages 23 through 26.
NOTE
Item
Number
Quantity Description
001 1b
1
2
008 2Screw
217 1
1
721 1
101 1
102
1
104 1
105
007 1
201 1
204a1
204b1
207 2
1
225 8Screw
1
1
1
1
1
1
401 1
4Screw
1
1
2
1
501 1
502 1
2Screw (SAE A,B,C 2 bolt)
4Screw (SAE 4 bolt, SAE D)
Item Description
Number Quantity
2Washer (SAE A,B,C 2 bolt)
4Washer (SAE 4 bolt, SAE D)
507 4Screw
508 1Cover Plate
504