Parker Hydraulic Pump Repair Manuals provide you with detailed service repair information. It will help you to better understand about the tools, tests, troubleshooting and adjustments as well as perfect instructions for routine maintenance, servicing and repair of hydraulic pumps.
Mount the pump in a vise with the shaft end pointingdown. Index mark all sections with a punch. Besure to align these marks when reassembling.
Remove the 4 cap screws on single units, or the 4 hex nuts, studs, and washers on multiple units with a socket wrench.
Lift off the port end cover.If necessary to pry loose, refer to caution note.If the thrust plate remains in the gear housing, it can be tapped out later with a wooden hammer handle. Be careful not to distort the thrust plate.
Lift the gear housing from the gears. Take care not to damage machined surfaces. For PGP031/051- Pry the gear housing from the gears and off the dowels from opposite sides, taking care not to damage machined surfaces.
For multiple assemblies
Carefully remove the drive and driven gears, without allowing the teeth to come into rough handling contact. Keep these gears together, because they are a matched set. Examine and replace if necessary.(See page 9.)
For multiple assemblies only.
Lift or pry off the bearing carrier carefully to prevent damage to contact face and edges. For PGP031/051, pry the bearing carrier off the dowels from opposite sides. Take care not to damage the machined surfaces. Lift off the bearing carrier.
For multiple assemblies
Remove the drive gear connecting shaft.
For multiple assemblies only.
Lift or pry off the first section gear housing. Be careful not to damage machined surfaces. If the
thrust plate remains in the gear housing, remove as described in Step 3.
Remove the driven gear and the integral gear and drive shaft. Keep these together as they are a matched set. Examine and replace if necessary.Be careful not to damage the machined surfaces of the gears.
Pry the thrust plates from the shaft end cover, port end cover, or bearing carrier with a screwdriver or similar tool. Avoid distorting the thrust plates. Visually inspect thrust plates for wear or damage. Replace if necessary. (See page 9.) Remove and discard all rubber pocket seals and gasket seals.
Examine all roller bearings for scoring, spalling, or pitting. If replacement is necessary, remove the bearings with a bearing puller.
It is generally advisable to replace ring seals when rebuilding the unit. To replace, remove the drive gear bearing with a bearing puller, and remove the ring seal from the bottom of the bearing bore.
If the pump is equipped with an out-board bearing, place the shaft end cover in a vise with the mounting face up.Remove the bearing snap ring with a small screwdriver or awl.
Use a bearing puller to remove the outboard bearing.
With the mounting face down, remove the double lip seal by inserting the special seal removal tool (see Tool List Pg. 10) into the notch between the double lip seal and the shaft end cover. Tap the seal out and discard.
Stone off all machined surfaces with a medium-grit, carborundum stone.
If the bearings have been removed, deburr bearing bores. Rinse parts in a solvent. Air blast all parts and wipe with a clean, lintless cloth before starting assembly
Grip the shaft end cover in a vise with the mounting face down. Examine the plug or the 2 check valves to be sure that they’re tightly in place. Replacement is necessary only if parts are damaged. Remove with a screwdriver or a special check valve tool (see Tool List page 10).
If plug or check valves are being replaced, screw in new parts tightly. Stake the plug with a prick punch at both ends of the screwdriver slot and around the edges. Screw the check valves in tightly with the tool. Peen edge of hole 1/32″ to 1/16″ with 1-1/2″ diameter steel ball.
ASSEMBLY STEPS 5, 6, 7, 9 AND 11 APPLY TO THE SHAFT END COVER, BEARING CARRIERS, AND THE PORT END COVER.
If the ring seals are being replaced, insert into the bottom of drive the gear bearing bore. The notch in the ring seal MUST BE VISIBLE. This is a check to be certain that the notched side is next to the bearing.
If any bearings have been removed from the shaft end cover, port end cover, or bearing carrier, replace the bearings by pressing them into the bearing bore with an arbor press.
Before inserting a new lip seal in the shaft end cover, coat the outer edge of the lip seal and its recess with Permatex Aviation Form-A- Gasket No. 3 Non-hardening SealanTM or equivalent. With the metal side of the lip seal up, press it into the mounting flange side of the shaft end cover with an arbor press and bar (See Tool List page10). On the PGP030/031 series, make certain that the lip seal is fully seated in the recess. On the PGP050/051 series, do not attempt to bottom-out the seal; press it in only until it is flush with the face of the recess. Wipe off surplus sealant.
Check all thrust plates for wear. Replace if necessary (see page 9).Note that the thrust plates for pumps and motors are different. Pump thrust plates have a single relief pocket and must be installed with this groove on the high pressure side.
Motor thrust plates are grooved on both sides.For PGP031/051, the relief groove on all the unidirectional thrust plates must be towards the high pressure (outlet) side of the pump.
PGP030/050 series pump and motor plates resemble the motor plate illustration.
Grip the shaft end cover in a vise with the mounting face down. Cut 2 pocket seals 7/32” long
from the pocket seal strip. Grease these pocket seals well and insert them into the middle slots on the reverse side of the thrust plate.
With the pocket seals facing down, place the thrust plate over the bearings in the shaft end cover. Tap thrust plate with a soft hammer to about 1/32″ from the machined surface.
Cut 4 pocket seals approximately 1/4″ long from the pocket seal strip. Insert one pocket seal into each of the slots in the thrust plate. Push each pocket seal all the way in so that it touches the roller bearings. Tap the thrust plate down firmly against the machined surface with a soft hammer. Use a sharp razor blade to trim the exposed end of the pocket seal square and flush with the thrust plate.
Insert the splined end of the drive shaft into the special steel sleeve (see Tool List page 10). Lightly grease the drive shaft and sleeve. Insert the integral gear and drive shaft with sleeve into the shaft end cover with a twisting motion. Be careful not to damage the double lip seal. Push down carefully until the gear rests against the thrust plate. Remove the steel sleeve. Insert the driven gear.
Grease the new gasket seals and insert them into the grooves in both sides of all gear housings.For the PGP031/051 – Examine all dowel pins. (See page 9.)* Before inserting a pin, make certain that the hole is clean and free from burrs. Start the pin into the hole gently and straight, tapping lightly with a soft hammer.
Slide the first section gear housing over the gears and tap it with a soft hammer until it rests tightly against the shaft end cover.Be careful not to pinch the gasket seal. Squirt oil over the gears to provide initial lubrication when the pump is started.
For the PGP031/051-Line up the dowels with the matching holes. When the parts are parallel, squeeze them together or gently tap alternately over dowels with a plastic hammer until the parts become parallel and move smoothly together. Do not force.
With the thrust plates mounted on the bearing carrier (as in steps 9, 10,11), position it on the gear housing so that the roller bearings receive the journals of the drive and driven gears. Make sure that the drain port in the bearing carrier is on the suction or inlet side if the unit is being built as a pump. (Motors do not have drain vents in the bearing carrier.) Make sure that the index marks are properly aligned. Insert dowel pins(PGP031/051 only).For multiple assemblies only.
Insert the connecting shaft in the spline of the drive gear.
For multiple assemblies only
Insert the drive and the driven gears of the second section into their respective bearings.Make certain gears are in contact with the thrust plate face.
For multiple assemblies only.
Slide the second section gear housing over the gears and tap it tight against the bearing carrier with a soft hammer. Be careful not to pinch the gasket seal. Squirt oil over the gears to provide
initial lubrication when pump is started. For PGP031/051 line up the dowels and the holes in the
2 castings. When parts are parallel, squeeze them together or gently tap alternately over the dowels with a plastic hammer until parts move smoothly together. Do not force. Insert dowel pins (PGP031/051only).
For multiple assemblies only
Place the port end cover over the gear journals and tap tightly against the gear housing. Be careful not to pinch the gasket seal. For PGP031/051 Align the dowels with the holes in the mating casting. Being careful not to pinch the gasket seal, tap the port end cover lightly in the center between bearing bores to engage the dowels and to move parts together in final seating.
Thread the 4 fasteners (cap screws and washers, or studs, washers, and nuts) into the shaft end cover and tighten alternately or cross-corner. Rotate the drive shaft with a 6″ wrench to make certain there is no binding in the pump.
After the fasteners are tight and you are sure there is no internal binding, torque the diagonally opposite fasteners to 200 ft. lbs. (2400 in. lbs.).
If the unit is equipped with an outboard bearing, guide the bearing into its recess in the shaft end cover. This is not a press fit. Insert the snap ring into its groove to retain the outboard bearing.
- PGP030/031 Series /PGP050/051 Series Service Manual
- • Arbor press
- • 1-1/2″ dia. steel ball
- • Bearing puller (Owatonna Tool Co. MD-956 or
- • Clean, lintless cloths
- • Deburring tool (an old file with the cutting teeth
- ground off)
- • Machinists hammer
- • Soft hammer
- • Permatex Aviation Form-A-Gasket No. 3
- Non-hardening SealantTM or equivalent
- • Medium-grit, carborundum stone
- • Oil and grease
- • Snap-ring pliers
- • Prick punch
- • Sharp, razor blade
- • Scale (1/32″ for graduations)
- • Small screwdriver
- • Torque wrench
- • Vise with 6″ minimum open spread
- • Bar for lip seal installation
- Note: For P30/P31, use 1-3/4″ dia. by 2 bar.
- For P50/P51, use 2-1/2″ dia. by 2″ bar.
- • Special steel sleeve
Materials: CAUTION: 1. If prying off sections becomes necessary, take extreme care not to mar or damage machined surfaces. Excessive force while prying can result in misalignment and seriously damage parts. 2. Do not force parts during assembly, and never use an iron hammer. 3. Gears are closely matched, therefore they must be kept together as sets, when removed from a unit. Handle with care to avoid damage to the journals or teeth. 4. Never hammer roller bearings into bores. Use only an arbor press or other suitable tool
If you have any questions about the maintenance of Parker hydraulic pumps, you can always ask our professional technicians
Guidelines for acceptable wear
Wear in excess of .005″ cutout necessitates replacement of the gear housing. Place a straight-edge across the bore. If you can slip a .005″ feeler gage under the straight-edge in the cut-out area, replace the gear housing.
Pressure pushes the gears against the housing on the low pressure side. As the hubs and bearings wear, the cutout becomes more pronounced.
Excessive cutout in a short period of time indicates excessive pressure or oil contamination. If the relief valve settings are within prescribed limits, check for shock pressures or tampering. Withdraw oil sample and check it and the tank for dirt.
Where cut-out is moderate, .005″ or less, the gear housing is in good condition, and both ports are of the same size, the housing may be flipped over and reused.
Any wear on the gear hubs detectable by touch, or in excess of .002″ necessitates replacement. Scoring, grooving, or burring of the outside diameter of teeth requires replacement. Nicking, grooving, or fretting of teeth surfaces also necessitates replacement.
Replace if there is any wear detectable by touch in the seal areas or at the drive coupling. .002″ wear is the maximum allowable. Wear in the shaft seal areas indicates oil contamination. Wear or damage to splines, keys or keyways necessitates replacement.
The thrust plates seal the gear section at the sides of the gears. Wear here will allow internal slippage, meaning the oil will bypass within the pump. The maximum wear allowable is .002″.
Replace the thrust plates if they are scored, eroded or pitted. Check the center of the thrust plates where the gears mesh. Erosion here indicates oil contamination. Pitted thrust plates indicate cavitation or oil aeration. Discolored thrust plates indicate overheating, probably insufficient oil.
If either the dowel pin or dowel hole is damaged, the pin, machined casting, or both, must be replaced. If more than reasonable force is required to seat dowels, the cause may be poorly deburred or dirty parts; cocking of dowel in the hole or improper pin-to-hole fit.
If the gears are replaced; the bearings must also be replaced. Bearings should fit into the bore with a light press fit. A near, hand-fit Is allowable.
Seals and Gaskets
Replace all of the rubber and polymer seals whenever disassembling the pump. Include all of the “O” rings, the pocket seals behind the thrust plates, the shaft seal, and the gasket seals.
Examine the small check valves in the shaft end cover to make sure that they are intact and functioning. If there are no check valves here, make sure that the high pressure side of the shaft end cover is plugged.
parker hydraulic pump FAQ
How do you adjust a Parker hydraulic pump?
Parker hydraulic pumps are designed with an adjustable hydraulic pump shaft. This allows the hydraulic pump to be adjusted so that it will work with different size cylinders.
Adjust the Parker pump by loosening the lock nut on top of the pump rod and turning the adjusting screw at the bottom of the shaft. Turn the screw until it is loose, then tighten it again by hand. After tightening, check to make sure that there is no play in the shaft. If there is play, loosen the screw again and turn it in or out until there is no more play in the shaft. Then tighten it down again by hand and recheck for play. If there still isn’t any play, then your adjustment is complete.
Where are Parker fittings made?
Parker hydraulic pumps are made in the United States. We’ve been an industry leader since the beginning, and we believe in the value of American manufacturing.
Parker hydraulic pumps are built in our manufacturing facility in Piqua, Ohio. This facility is a state-of-the-art production plant with over 300,000 square feet and more than 120 employees. We also have another manufacturing facility in Mexico that produces hydraulic pumps for export markets.
Who owns Parker hydraulics?
Parker Hydraulics is owned by Danaher Corporation. They are an American global science and technology company operating in more than 60 countries, with about 25,000 employees worldwide.
Danaher Corporation is a Fortune 500 company headquartered in Washington, D.C., United States, with 2015 annual sales of $19 billion and approximately 50,000 employees. Danaher has been included in the S&P 500 Index since June 2010, and has been traded on the New York Stock Exchange under the symbol DHR since 1983.