Valve Plates Swash Plates and Retainer Plates
Valve plates swash plates cradles retainer plates and ball guides for axial and bent axis piston pumps lapped and ground to the original drawing.
Product Overview
These are the stationary parts the rotating group runs against. The valve plate takes the pressure change every revolution, the swash plate carries the shoe load, and the retainer plate and ball guide hold the shoes flat against it. All of them are finish ground or lapped after heat treatment, because a part that is hard but not flat wears the group it runs against.
| Rexroth pattern frames | A2F A2FO A2FM A4V A4VSO A4VG A6V A6VM A7V A7VO A8VO A10VO A10VG A11VO A11VG |
|---|---|
| Parts | Valve plate, swash plate, cradle, retainer plate, ball guide, press pin, bearing seat |
Key Benefits
- Lapped valve plate faces so the block seals rather than merely touches
- Swash plate and cradle ground after hardening to remove distortion
- Kidney port geometry follows the original drawing including timing notches
- Available singly, so one failed part does not force a whole rotary group order
Application Scenarios
- Rebuild of excavator, loader and industrial pumps
- Replacing a plate scored by a single failed shoe
- Restoring pumps that have lost efficiency without visible damage elsewhere
- Stocking common plates for a rebuild shop
Who It Is For
- Rebuild shops
- Distributors
- Maintenance workshops
- Exchange unit builders
Problems It Solves
- The valve plate face is scored and the pump will not hold pressure
- The swash plate has picked up where a shoe failed
- The retainer plate is worn and the shoes are lifting
- Timing notches on a cheap replacement plate did not match and the pump ran noisy
Technical Features
- Bearing steel or bronze faced steel depending on the frame
- Faces lapped after grinding
- Kidney ports and timing notches to the original geometry
- Retainer plates and ball guides matched to the block
- Press pins, bearing seats and springs available with the plate
Specifications
Performance figures depend on the exact variant, so we confirm them against your model code rather than publishing a number that may not apply to your pump.
| Valve plate material | Bearing steel or bronze faced steel by frame |
|---|---|
| Face finish | Ground then lapped |
| Swash plate | Hardened and ground after heat treatment |
| Port geometry | Kidney ports and timing notches to the original drawing |
| Related parts | Retainer plate, ball guide, press pin, bearing seat, spring set |
| Packing | Oiled and vacuum sealed |
Materials
| Cylinder blocks | Case hardening steel with a sintered bronze running face, bonded and machined after sintering |
|---|---|
| Pistons and shoes | Case hardening steel with a bronze shoe face, swaged and hydrostatically balanced |
| Valve plates | Bearing steel or bronze faced steel depending on the frame, lapped to a mirror finish |
| Drive shafts | Alloy steel, carburised and hardened on the spline and bearing seats, ground on centres |
| Vanes and rotors | High speed tool steel and case hardening steel, hardened and ground on all working faces |
| Cam rings | Bearing quality alloy steel, through hardened then profile ground |
| Seals | Nitrile as standard, fluorocarbon or polyurethane on request for hot or fire resistant fluid duty |
Manufacturing Process
- Turning and millingBlanks are turned and milled from certified bar and forging stock on CNC machines.
- Heat treatmentCarburising, quenching, tempering or nitriding to the route the original part uses.
- GrindingBores, spline seats and running faces are ground after heat treatment so distortion is removed.
- Lapping and superfinishingValve plates, shoe faces and block faces are lapped so the pair seals under pressure.
- InspectionDimensions, hardness and surface finish are recorded against the drawing on a sampling plan.
- Assembly and testComplete pumps are built, run in and tested for efficiency, leakage and noise before packing.
Quality Control
- Incoming material certificates are checked against the grade called for on the drawing.
- Hardness is measured after heat treatment on every batch and recorded on the batch card.
- Critical bores and running faces are gauged against the drawing tolerance, not against a sample part.
- Mating parts are matched as a set so the block, shoes and valve plate run in together.
- Rebuilt pumps are bench tested for volumetric efficiency, external leakage and sound level.
- Parts are cleaned, oiled and vacuum sealed so they arrive without surface rust.
Certifications and Documentation
Supplied on request with an order. We do not claim approvals we cannot evidence.
| Material certificate | Mill certificate for the steel grade used in the batch |
|---|---|
| Hardness report | Surface and core hardness readings after heat treatment |
| Dimensional report | Measured values for the critical features named on the drawing |
| Test bench report | Flow, efficiency, leakage and sound readings for a rebuilt pump |
| Packing list and photographs | Carton contents and photographs of the packed goods before shipment |
Customization Options
- Shaft and splineKeyed, straight or splined shaft ends built to your sample or drawing.
- Port and mountingFlange, thread and mounting pattern matched to the pump already on the machine.
- Seal materialNitrile, fluorocarbon or polyurethane for hot oil, fire resistant fluid or low temperature duty.
- Rotation and displacementLeft or right hand rotation and the displacement code your circuit was set up for.
- Marking and packingNeutral packing, your own carton artwork and your own part number laser marked on the part.
Comparison With Other Products
| Point | New Valve Plate | Relapping the Old Plate | Complete Rotary Group |
|---|---|---|---|
| Cost | Low | Lowest | Highest |
| When it works | Face scored or worn through the hardened layer | Very light marking | Block and pistons also worn |
| Effect on noise | Correct timing restores quiet running | Unchanged | Correct timing restored |
| Fitted with | New or measured good block | Existing block | Full set |
Use Guide
- Check the block face at the same time. The two parts wear as a pair.
- Confirm the rotation, because valve plates are handed.
- Do not lap a new plate. It is supplied ready to fit.
- Fit dry parts with clean oil on the faces.
- Run in at low pressure and check case drain flow.
Product Photographs
Related Products
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Cylinder blocks for axial and bent axis piston pumps with sintered bronze running faces bonded and machined after sintering then lapped flat.
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Hydraulic Piston Rings
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Frequently Asked Questions
Are valve plates handed for rotation?
Yes. A plate fitted for the wrong rotation will run noisy and fail quickly. Tell us the rotation with the model code.
Can a scored plate be reground?
Only if the hardened layer is still intact. Once it is through, a new plate is the safer repair.
Do timing notches matter?
Yes. They control how pressure changes as each bore crosses over, which is what sets pump noise and peak stress.
Do you supply swash plates for the closed circuit families?
Yes, for the A4VG, A10VG and A11VG frames among others.
Can I order a plate on its own?
Yes. Single part orders are welcome.
Send Us the Model Code and We Will Quote
Tell us the model code stamped on the pump, the quantity and your delivery port. A quotation with lead time usually comes back within one working day.