Why unnecessary excavator bucket pin repair quickly adds up in cost

In Iowa, USA, a major municipality experienced a recurring problem with its Liebherr 900 excavators, which are used for important infrastructural work like digging trenches and manholes. The four traditional straight pivot pins holding the bucket section together frequently experienced loosening in the lug ears, leading to problems operating the bucket.

When put into numbers the extent of the problem is clear: the municipality was forced to replace the bucket pins 18 times over the first eight years of owning the excavator. On average that meant more than two of the four pivot pins in the bucket was replaced every year.

Because of the recurring problem with lug wear, excavators had to be taken out of service and undergo line boring in a workshop to keep them in working condition. This is not only costly in terms of maintenance, but also time consuming, leading to prolonged downtime and a higher TCO. As the municipality did not have many excavators in its fleet, this created a significant challenge, causing entire projects to be put on hold during repair time.

The Expander System delivers an immediate upgrade for bucket pin applications

With the excavators accumulating unexpected costs year after year, the municipality needed to find a solution. They decided to test the Expander System to evaluate whether it would improve upon the traditional pivot pins previously used, starting initially by installing one in the bucket area.

Already during the first installation a clear difference was observable, as it was possible to install the Expander System directly on site within a couple of hours with no need for a workshop visit, providing an instant time and cost saving for the municipality.

After a problem-free first year with the Expander System pivot pin, the municipality decided to scale and install one more. This was quickly followed by installing a third and fourth pin, so the entire bucket area on the excavator was secured with Expander System pins.

How is the Expander System different to a standard bucket pin or pivot pin?

Standard straight pins require the lug holes they are fitted into to be slightly larger than the pin itself in order to be installed. This in turn means reduced precision as well as an inevitable wear on the lugs as the pin moves against the lug hole it is fitted into during operation of the machine. Additionally, pressure on the pin is not evenly distributed, but rather, loaded onto a small area, further contributing to deformation. The lug hole eventually wears so much that a repair is unavoidable – as was the case in the Liebherr 900 excavator.

In the Expander System, the pivot pin is tapered at both ends and fitted with expansion sleeves. When the pin is fitted, the tensioning fasteners in the sleeves are tightened until the sleeve expands to conform to the shape of the lugs. This ensures a more even distribution of pressure across the lug hole, eliminates the issue of harsh pin movement, putting an end to lug wear damage, and solving the issue of unnecessary workshop visits and downtime.

A proven bucket pin solution for the Liebherr 900 with potential to scale

In the Liebherr 900 excavator the solution delivered satisfying results, and as a result the municipality planned for a wider roll-out.

“We would recommend the Expander System to anyone using heavy equipment who is having issues with pivot pins,” a foreman working at the municipality said.

“We have also told maintenance personnel from other cities about the Expander System and plan to use the solution on other machines in our fleet.”

KEY TAKEWAYS

Use case:

Upgrading bucket pins with Expander System to improve excavator uptime

Client:

Large municipality

Location:

Iowa, USA

Benefits gained:

• Eliminated need to take excavators out of service due to pivot pin wear
• Eliminated risk of projects being put on hold due to excavator downtime
• New pins installable in the field to save time and money
• TCO boost from new solution