Sometimes a single service call can turn into a full-fledged rescue operation.
That was the case with the Liebherr 944 excavator, which we were called to due to a blocked rotation. On site, Artur conducted preliminary pressure measurements – the diagnosis was quick: a damaged rotation brake coil.
Initial successes and new problems
After replacing the coil, the rotation came back to life, but unfortunately, not everything was working as it should. One of the tracks was not pulling, and the arm was working sluggishly. This was a signal that the problem might lie deeper. We then proceeded to more detailed diagnostics – measurements on the main distributor. It turned out that one pump section was not producing any pressure, while the other barely reached 160-200 bar.
Metal shavings disaster in the tank
We decided to take a look inside the tank. What we found there could scare any mechanic – the entire system was contaminated with metal shavings. After consulting with the client, a decision was made to disassemble the main pump and the reducer. Additionally, we also took the rotation pump and rotation motor – shavings could be everywhere.
Disassembly of LPVD 140 – puzzles in a state of agony
Upon arriving at the workshop, Marcin and I began to disassemble the LPVD 140 pump. First, we removed the regulators, readers, and control pistons. Then we moved on to unscrewing the bolts of the closing plate. The view? A disaster. Damaged cylinder, seized rotary group, separator in pieces. The pistons were destroyed, and the whole thing looked like a hydraulic massacre. We identified the cause of the failure: the separator had been completely destroyed, and shavings from it had passed through the entire rotary group, damaging the pistons, cylinder, and working surfaces. This was not just a typical case of wear – it was a cascading failure caused by a lack of earlier response to the first symptoms. Shavings were literally everywhere – the previous failure of the rotation pump had apparently not been properly cleaned. It was claimed that the oil had been changed, but looking at the condition of the components, it was hard to believe. The domino effect – one failure led to another.
What can be salvaged?
From this pump, only the housings, casing, shafts, and possibly the regulators could be salvaged. All main components need to be replaced. The client was very pressed for time, so he decided to purchase a reducer and pump from our stock. This allowed us to proceed directly to assembly.
Take care of your machines!
This case is a perfect example of how one neglected fault can lead to an avalanche of problems. Therefore, regularly change the hydraulic oil, filter it, check the condition of the pumps, and do not underestimate even minor symptoms of failure.
See the entire course of the operation on YouTube – Breakdown in Liebherr 944:
