# A slewing ring at the end of its life. How long could it keep running like that? Liebherr A906

> Replacing the slewing ring on a 2009 Liebherr 906 excavator: 2 cm of play in the slewing bearing, plugging the swivel joint lines, lifting the upper carriage, fitting a new ring and 88 new bolts with copper grease torqued to 620 Nm.

![A Slewing Ring at the End of Its Life. How Long Could It Run Like That? Liebherr 906](https://wibako.com/media/articles/article-836/x0omi80wyvc.webp)

A 2009 **Liebherr 906** excavator drove into our workshop and it was immediately clear what needed doing: there was **about 2 cm of play** in the slew. This time the culprit was not chipped teeth but a **worn-out slewing bearing**. With that much play the ring has to be replaced, no question.

## Preparation

The machine was covered in a thick layer of mud, so we started with a thorough wash using chemicals and a pressure washer – when replacing a slewing ring, a clean joint area is essential. Then:

- we cracked the bolts loose with a wrench and extension bar (they were very tight) and then removed them with a pneumatic wrench,
- at the swivel joint we disconnected and plugged the travel lines, the return line from the hydraulic motors to the tank and the gear change line – so the machine could still be started and supported on its boom,
- we lifted the upper carriage with a forklift at the rear and with the boom at the front.

One bolt had been missed and the upper carriage lifted together with the ring – fortunately, once the forklift was in place, we simply removed it and took out the old ring.

## Fitting the new ring

The new ring went in straight after the old one came out – the machine was secured, so no time was lost. We also replaced **the full set of bolts: 40 in the upper row and 48 in the lower row, 88 in total**. Every bolt was coated with **copper grease**, which protects the thread from corrosion and seizing – so that at the next replacement, many years from now, they can be removed without trouble.

After pre-tightening we torqued all bolts with a torque wrench to **620 Nm** as specified by the manufacturer – one after another, marking each, in both the upper and lower rows.

## Result

The play is gone and the slew runs smoothly without knocking. After refitting the covers the machine was ready to be handed back to the customer.

## Takeaways

- Slewing play increases gradually – the longer a machine works with it, the greater the risk of damaging the structure and bolts.
- When replacing a slewing ring we always replace the complete set of bolts and torque them to specification.
- Copper grease on the threads makes the next repair easier.

We replace slewing rings in our workshop and, if needed, in the field. See our [construction machinery service](https://wibako.com/services/construction-machinery-service).

**Watch the repair video:** [A Slewing Ring at the End of Its Life. How Long Could It Run Like That? Liebherr 906](https://wibako.com/about-us/video/836-a-slewing-ring-at-the-end-of-its-life-how-long-could-it-run-like-that-liebherr-906)

Published: 2026-07-17

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Source: https://wibako.com/about-us/news/837-a-slewing-ring-at-the-end-of-its-life-how-long-could-it-keep-running-like-that-liebherr-a906
Contact: +48338704200, biuro@wibako.pl