A piston pump that fails at 4,000 hours rarely failed at 4,000 hours. It failed at 2,800, when the first particles passed through the servo and nobody noticed the oil was running four degrees hotter than it should.
Three early signals
1. Slow function at low idle. If the arm drifts behind the other functions at idle but keeps up at full throttle, the pump is losing volumetric efficiency. That is wear, not a settings problem.
2. Rising oil temperature. Internal leakage converts pressure into heat. A 5 °C rise over a month with the same workload is worth investigating.
3. Metal in the filter. Cut the filter open. Bronze-coloured particles point at the slipper and swash plate; steel flakes suggest the rotating group.
What to do before removal
Record the pump pressure at relief, the standby pressure and the flow at each function. A replacement pump installed into a contaminated system will fail again in months — flush the tank, clean the suction strainer and check the cooler circuit first.
When replacement beats repair
If the housing is scored or the swash plate shows more than 0.05 mm of wear, repair costs approach a new assembly. On common references such as the Komatsu 708-2L series, replacement is usually the faster route.
Send us the part number and a photo of the pump nameplate and we will confirm the correct reference before you order.