By Published On: February 23, 2021Categories: Case Studies, Mining0 Comments


To create a robust new seal kit for leg jack cylinders, ensuring reliability in new fluids and higher application demands.


A complete redesign utilizing state-of-the-art sealing profiles in System Seals’ high-performance materials.


Independent testing showed the System Seals kits to last four times as long as traditional seals, with the test ending due to timing restraints, not seal failure.

When an American re-manufacturer of leg jack cylinders set out to compete with Europe’s global market leaders, the company asked System Seals to redesign the standard OEM seals in a way that would raise the bar for teh entire mining industry.

Mining operators have placed greater demands on sealing systems to increase safety and reduce environmental concerns. With uptime and safety translating directly into revenue; a decision was made to break away from the old OEM sealing designs of the past, and look for a new design with significant improvements.

System Seals began developing a complete sealing system designed specifically for the company’s new American leg jack cylinders. Placing safety as a top concern, it was vital that the new seals were engineered to withstand the extreme demands of working underground, while preventing even the slightest drift or bypass. This meant only our most robust profiles and materials could be used.

To make the sealing system as reliable as possible, we started with our type 324 “Rambo” wiper; a custom design that sheds water and aggressively scrapes contaminants from the ram. The rod and piston seals included robust anti-extrusion devices with sealing elements made from our proprietary MP03 material. MP03 is uniquely designed to operate in water and water-based fluids, in a wide range of temperatures, and also exhibits premium wear resistance when compared to typically used polyurethane materials.

To ensure longer seal life and smooth operation, we chose our proprietary MTC1 to provide guidance and maintain metal to metal clearances. MTC1 is a high compressive strength material with a high yield stress, low swell in water, and low wear rate when compared to traditionally used guidance materials. Additional research also showed that the three most common materials used for guidance left some form of scoring on the rod, System Seals MTC1 left only polishing streaks, which had no significant change in surface roughness.

Before the prototypes were even sent, independent European researchers remained skeptical that significant improvements were even possible. Then the testing began. The initial goal was to safely reach 30,000 cycles. After achieving the goal with zero leakage, the testing team decided to run an additional 30,000 cycles. Ultimately, the test was arbitrarily terminated at 80,000 cycles by the customer due to time restraints.

Review of the test cylinder and seals showed zero signs of wear or damage on the cylinder bores or chrome rods. All internal components were relatively clean, with no visual evidence of dirt or contamination. And as expected, the seals and guide bands visually appeared to be in excellent condition with little signs of use.

After proving a minimum life increase of at least 2.5 times, the new System Seals leg jack sealing system began to redefine the industry’s expectations, and helped position the American manufacturer at the top of the market for both new and rebuilt leg cylinders.

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