Hydraulic Fluid, Conditioning and Storage

All of the components in a properly functioning mobile hydraulic system work as a team. Take one of the players away and the machine will cease to function, or limp off to the sideline for some expensive time off. Until recently, an important member of the team really hasn't received the attention it deserves. Hydraulic oil has been the water boy of sorts, an afterthought in the overall layout of the system. But without hydraulic oil, the machine would not move at all.

Published by Sperry Vickers in 1967, Mobile Hydraulics Manual M-2990-A puts coverage of the oil in the back of the book as Appendix A. The manual, for its time, is comprehensive in its coverage of a mobile off-highway machine's hydraulic system. The introductory paragraph on fluid says, "The oil in a hydraulic system serves as the power transmission medium. It is also the system's lubricant and coolant. Selection of the proper oil is a requirement for satisfactory system performance and life."

Following that the hydraulic oil gets covered through a relatively quick look at viscosity and cold-weather conditions. The industry has evolved in the 40 years since the manual was published, while some basics of the hydraulic system hold true.

From the high-horsepower engines in road building equipment to the tight tolerances in the hydraulic system of a cotton harvester present machines are much less tolerant to dust and other contaminants. Today, hydraulic fluid deserves more than a mention in an appendix. Machine performance can be increased by fine-tuning the oil through careful base oil and additive selection. Like the more expensive parts in the fluid system, the condition of the fluid is more significant now than ever, and it's driving improvements in filter design. Plus, it's more critical than ever to anticipate machine problems by monitoring engine and hydraulic oils.

Laboratories can read the fluid to determine machine health, information that end-users can utilize to better plan preventative maintenance schedules. Engineers at OEMs can make use of this information, too, in order to better understand how a machine is performing in the field.

End-users and OEMs are realizing the importance of including a fluid analysis program in their preventative maintenance routines. Recently, Terex Roadbuilding, Oklahoma City, announced its Managed Maintenance Fluid Analysis Program.

Working with Polaris Laboratories, headquartered in Indianapolis, the program covers equipment from the manufacturer's mobile concrete and asphalt lines, including slipform pavers, asphalt pavers and material transfer vehicles.

"Terex focuses on producing quality capital equipment that delivers productivity, return on investment and cost effectiveness that today's value-conscious customer expects," says Larry Meyer, Terex Roadbuilding senior director - customer service and support. "We believe the services Polaris can provide will be of tremendous support in continuing that focus."

Specifically, the new Terex Managed Maintenance Fluid Analysis program gives Terex customers a one-stop shop for receiving accurate, repeatable and traceable results. Fluid testing is performed in one of Polaris' ISO 17025 A2LA-accredited labs located in Indianapolis, Houston or Salt Lake City. The results provide a picture of fluid contamination as well as the internal condition of a component or system, so minor issues can be found and corrected before they become a major problem.

"There are literally hundreds of indicators that the fluid analysis program can use to detect potential problems," says Meyer. "High silica, for instance, indicates a filtering inlet issue, and iron particles in the fluid can be a gauge of bearing or gear wear."

For Terex, tracking the results can be done through the company's website. Customers log into the Terex Horizon Reports to obtain analysis results. The reporting software helps customers get the most from the information by offering the ability to build an archive of previously run analyses in order to track trends that can help diagnose small issues before they turn into more expensive service items.