This was the case with the Volvo EW160B excavator, which started to operate slowly and lose power. Diagnosis? Likely failure of the Linde HPR 135 hydraulic pump. Time for a service action!

Symptoms that do not bode well

The report was clear: weak machine, sluggish movements. Our service team needed no further encouragement – such symptoms are often a prelude to more serious problems with the hydraulic system. Upon arrival and preliminary verification, the suspicions were confirmed: regeneration of the hydraulic pump was necessary.

Time to act – disassembly and diagnosis

The first step was to unscrew the mounting elements of the coupling flange attaching the pump to the internal combustion engine. Marcin, our hydraulic specialist, immediately got to work. He disassembles the regulator, unscrews the screws of the closing plate, and removes it. Even at this stage, it is clear that the pump had been previously repaired – the lubrication socket of the bearings showed signs of earlier regeneration.

What went wrong?

This is a fairly common case – the lubrication socket is the Achilles' heel of this series of pumps. Its damage results in incorrect oil flow direction: instead of going to lubricate the swash plate and bearings, the oil enters the pump's interior, causing leaks and preventing maximum pressure from being achieved. Diagnosis confirmed – the culprit identified.

 

Disassembly into components

We extract the entire rotating group from the housing – shaft, cylinder, swash plate. We proceed to disassemble the separator brackets. The screws were screwed in with glue, so we heat the swash plate at the mounting point – this allows the screws to come out without any problem.

Inspection and analysis of technical condition

Next, everything goes for washing and thorough inspection. On the press, we disassemble the cylinder spring and check the condition of the rings. Unfortunately – they qualify for replacement, as does the outer cylinder sleeve. The main lubrication socket also does not hold dimensions – it is responsible for transmitting oil to the swash plate. If it is damaged, the entire system loses tightness and the pump cannot operate correctly.

Regeneration – surgical precision

We also disassembled the regulator and checked the coil. All verification results were recorded in the system. After preparing the parts, we proceeded to assembly. The cooperating parts were polished, the housings and closing plate were cleaned. We replaced the outer cylinder sleeve and the rings.

The biggest challenge – regeneration of the lubrication socket

We devoted the most attention to the problematic lubrication socket. We decided on regeneration, as the cost of a new one is very high – we pressed in a sleeve with original dimensions and appropriate hardness. We also checked the clearances on the shaft, pistons, and separator brackets. Finally – the closing plate, which needed to be precisely adjusted. Too small a clearance would risk quick wear and failure, too large would result in ineffective operation.

Tests and results – the final stretch

After assembling everything, it was time for tests. We connected four hoses – supply, main pressure, leaks, and control. Remember – before starting the pump, it must always be bled. Start-up at 1000 RPM and full control of parameters.

All values are normal, the pump works perfectly! The last stage is painting and shipping to the client.

If you want to see the entire regeneration process with your own eyes, be sure to watch our video on YouTube: Regeneration of Linde HPR 135 from the Volvo EW160B excavator. See how service looks in practice – from disassembly to tests on the test bench!