# A hydraulic pump repair revealed another problem – servicing a Sennebogen 730E

> Installing the hydraulic pump in a 2023 Sennebogen 730E material handler: coupling, main pump and slewing pump, filter change, tank cleaning, bleeding and pressure measurement. A load test revealed leaking grapple cylinders.

![A Hydraulic Pump Repair Revealed Another Problem... Sennebogen 730E Service](https://wibako.com/media/articles/article-828/lfap8iwrhhi.webp)

This time it is a 2023 **Sennebogen 730E** material handler. The customer removed the damaged hydraulic pump and delivered it to us for repair. In this episode we bring it back to the machine: we install the pumps, change the filters, clean the tank, start the machine and measure the pressure. The load test, however, revealed another problem.

## Installing the pumps

The pump came to us as a set of two pumps bolted together. On site we separated them to make it easier to fit the long, heavy main pump. The sequence:

- flange with coupling – bolts secured with thread locker,
- main pump, carefully aligned,
- slewing pump with a new O-ring and adapter,
- hydraulic lines and control solenoids.

## Filters and tank cleaning

After a pump failure, replacing the components alone is not enough. We removed all **return filter** elements together with their housings, because contamination collects at the bottom, and cleaned the tank thoroughly. Then we replaced the **suction filter** – first blowing the area around the cover clean with compressed air so no dirt could fall in.

## Bleeding, start-up and pressure measurement

The most important step of the whole job is **bleeding the pump** before the first start – only then do we fit the shaft. After filling with oil we connected a pressure gauge to monitor the pump pressure from the first seconds. The machine started, idled for a while to draw in oil and bleed the system, and then we checked the working pressure: approx. **365 bar, peaking at 375 bar**. The pump works correctly.

## Test with the operator: another fault

We tested the machine ourselves first, then the operator checked it under load in normal working conditions. That is when it turned out that **the grapple cylinders were leaking internally**. The customer asked us to fix them straight away so as not to extend the downtime. We removed the cylinders on site and took them to our workshop for reconditioning – more on that in the next episode.

## Takeaways

- After a pump replacement we always change the return and suction filters and clean the tank – debris from the failure would destroy the new pump.
- Bleeding the pump before start-up and measuring pressure are the basis of a correct commissioning.
- A load test with the operator catches faults that are invisible when the machine is standing.
- Fixing several faults in one visit reduces total machine downtime.

Every pump is inspected free of charge on the day it arrives. See: [hydraulic pump and motor repairs](https://wibako.com/services/repairs-of-hydraulic-pumps-and-motors) and [construction machinery service](https://wibako.com/services/construction-machinery-service).

**Watch the repair video:** [A Hydraulic Pump Repair Revealed Another Problem... Sennebogen 730E Service](https://wibako.com/about-us/video/828-a-hydraulic-pump-repair-revealed-another-problem-sennebogen-730e-service)

Published: 2026-05-29

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Source: https://wibako.com/about-us/news/829-a-hydraulic-pump-repair-revealed-another-problem-servicing-a-sennebogen-730e
Contact: +48338704200, biuro@wibako.pl