Repair of hydraulic pumps and motors – Bosch Rexroth Certified Workshop

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Certified repair on a Bosch Rexroth test bench

TFS Oleodinamica has a Bosch Rexroth-approved test bench for testing repaired hydraulic pumps and motors. Since 1997, as a Certified Excellence Service Partner, we have performed documented repairs on products from all major manufacturers: every repair is tracked, tested, and covered by original spare parts with direct access to the Bosch Rexroth warehouse.

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The repair process

1. Receipt and technical diagnosis – visual inspection and verification of functional parameters
2. Disassembly and wear analysis – inspection of pistons, bushings, valves, and sealing surfaces
3. Replacement with original spare parts – seal kits, pistons, spools, and manufacturer-certified components
4. Assembly and calibration – reassembly to design tolerances, adjustment of pressures and flow rates
5. Testing on a Bosch Rexroth test bench – comprehensive functional test with issuance of a technical report

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Bosch Rexroth-certified test bench

The TFS test bench is Bosch Rexroth-certified: it allows for the testing of axial piston pumps up to 500 bar and hydraulic motors, verifying flow rate, volumetric efficiency, and sealing. Each test cycle produces a signed technical report, delivered to the customer along with the repaired component.

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Brands we service

We repair hydraulic pumps and motors from the world’s leading manufacturers, using original parts or certified cross-reference parts and procedures validated by the manufacturer.

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Overhauling an excavator hydraulic pump

On excavators the main pump is almost always a variable displacement axial piston pump, often in tandem configuration: two pumps on the same shaft that together feed boom, arm, bucket, swing and travel. It is the hardest-working component on the machine, and when it fails the excavator stops. TFS overhauls excavator pumps from the main manufacturers, including Kawasaki (K3V, K3VL, K5V) and Bosch Rexroth (A8VO), and tests them on the bench before return.

Signs that the pump needs an overhaul

• Slow or weak movements, especially when several functions are combined
• Diesel engine losing revs or stalling under load: often the pump no longer regulates the power it absorbs
• Abnormal noise, whining or vibration around the pump
• Oil running hotter than usual and metal particles in the filters
• Increased case drain flow, a sign of internal leakage

The pump is not always to blame: a relief valve discharging, a worn control valve or a fault in the pilot circuit produce similar symptoms. This is why diagnosis starts from the machine and from measurements, not from replacement.

Kawasaki K3V, K3VL and K5V pumps

On Kawasaki K3V, K3VL and K5V pumps the failure we see most often concerns swash plate lubrication: when it fails, the swash plate seizes, the pump can no longer vary its displacement and the machine does not respond as it should. TFS is a Kawasaki Authorized Service Centre: it works to the manufacturer’s specifications with genuine parts, and repairs on Kawasaki pumps are covered by a 12-month warranty.

How we work on an excavator pump

The pump is dismantled, washed and measured component by component: pistons and slippers, cylinder block, valve plate, swash plate, bearings and regulator. Whatever is out of tolerance is replaced, the pump is reassembled to the manufacturer’s specifications and the regulator is set. Testing follows on the pump test bench, up to 470 bar and 600 l/min, with a report of the measured values.

One piece of advice we always give: after a pump failure, before refitting it, the circuit must be cleaned and the oil and filters replaced. Metal debris from the failed pump, left in the system, quickly ruins even a freshly overhauled pump. When needed we work directly on site with our on-site support.

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For a repair service or to verify the feasibility of repairing a specific component, contact the TFS technical team: we will respond within 24 business hours with an estimate of the time and cost of the repair.