Piston Pumps – Repair, Overhaul, and Testing on a Certified Test Bench

Types of piston pumps that TFS overhauls

TFS services fixed-displacement axial piston pumps with swash plates (Bosch Rexroth A2FO, A10FO series), variable-displacement pumps with DR/DRG/DFR/DFLR regulators (A10VSO, A4VSO, A11VLO), closed-loop pumps for hydrostatic transmissions (AA10V, AA4V), and radial piston pumps. The Kawasaki range covered includes K3V, K3VL, and K5V on excavators and earthmoving machinery. For each manufacturer’s model, the overhaul uses original spare parts and calibration procedures in accordance with the manufacturer’s service manual.

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Test bench overhaul procedure

Every pump received undergoes: receipt and visual inspection, disassembly with component cataloging, dimensional inspection of the cylinder block and shoes, verification of the inclined plate’s flatness, complete replacement of the OEM gasket kit, reassembly in a filtered atmosphere, hydraulic bench testing with measurement of flow rate, pressure, and volumetric efficiency. The test report includes performance curves and is signed by the responsible technician, ensuring full traceability of the service.

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On-site service and scheduled maintenance

For production applications, TFS organizes on-site service teams: field diagnostics, pump replacement with the machine in line, and support for restart. For fleets of identical pumps (quarries, steel mills, presses, shipbuilding plants), TFS implements preventive maintenance programs with scheduled overhaul cycles and management of spare parts held on consignment at the customer’s site. This approach drastically reduces machine downtime and allows interventions to be concentrated during scheduled shutdown periods.

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Brands we service: Bosch Rexroth – A10VSO and A4VSO piston pumps, Kawasaki K3V and K5V – Authorized Service Centre, Linde Hydraulics – hydrostatic transmissions, Hydreco – pumps for industrial vehicles, Parker – piston pumps, Denison Calzoni – piston pumps, Casappa – MVP axial piston pumps, Hawe – R-series radial piston pumps, Commercial Hydraulics – axial piston pumps, Nachi – PVS and PVD variable piston pumps, Uchida – AP2D piston pumps based on Rexroth technology, Voac Hydraulics – F11 and F12 axial piston pumps.

TFS services involved: pump and motor repair on test benches, overhaul of hydraulic components, testing and certification, on-site assistance, scheduled maintenance.

Application sectors: earthmoving, steel industry, Oil & Gas, marine, presses, agriculture, rail.

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Discontinued series: A1VO, A2FO, A4VBO, A4FM

Many piston pumps still in service belong to series no longer in the catalogue. When one of these units fails, the problem is not the repair itself but availability: the new spare part no longer exists, or it is quoted with lead times and prices that are out of the market. In these cases overhaul is not the cheaper option — it is often the only practicable one short of rebuilding the system.

TFS works on the legacy Bosch Rexroth series — including A1VO, A2FO, A4VBO, A4FM, A4VTG, A8VO, A10VSNO and A15VSO — with complete disassembly, dimensional inspection of internal components, remachining or replacement of worn parts and final testing on a certified test bench. Where the original spare part is no longer available, remachining the existing component is assessed.

Data sheets for the series we work on most frequently:

• Bosch Rexroth A1VO – data sheet (PDF)
• Bosch Rexroth A2FO – data sheet (PDF)
• Bosch Rexroth A4VBO – data sheet (PDF)
• Bosch Rexroth A4FM – data sheet (PDF)
• Bosch Rexroth A4VTG 33 – data sheet (PDF)
• Bosch Rexroth A10VSNO – data sheet (PDF)
• Bosch Rexroth A8VO – data sheet (PDF)
• Bosch Rexroth A15VSO – data sheet (PDF)

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Current series: A4VSO, A4VG, A10VSO

On series still in production, TFS overhaul work runs alongside the supply of new parts: when lead times are not compatible with plant downtime, repairing the existing unit puts the machine back in service sooner. We work on the sizes and control variants of the A4VSO, A4VG (series 32 and 40) and A10VSO (series 31 and 32) ranges, as well as Kawasaki K3V, K3VL and K5V pumps for earthmoving machinery.

• Bosch Rexroth A4VSO – data sheet (PDF)
• Bosch Rexroth A4VG 32 – data sheet (PDF)
• Bosch Rexroth A4VG 40 – data sheet (PDF)
• Bosch Rexroth A10VSO 31 – data sheet (PDF)
• Bosch Rexroth A10VSO 32 – data sheet (PDF)

Case study: variable-speed pumps

When a piston pump is paired with a variable-speed drive, consumption follows actual demand: Sytronix Bosch Rexroth Green Power.