Maintenance program

Akron Hydraulic is excited to announce a cost-effective new service that helps extend equipment life, a particularly welcome benefit at a time when equipment managers are in "maintenance mode" due to the current economic conditions.

Akron Hydraulic has launched a nationwide program to restore hydraulic directional control valves, which are found on nearly every piece of heavy equipment, including excavators, dozers, paving and drilling machines. Control valves are essential to productivity in the construction industry. Equipment owners will spend significantly less money rebuilding these valves to like-new tolerances instead of replacing them.

"In today's economy, equipment managers are looking to extend the life of their fleet and not spend a fortune doing it," said Mitch Langford, service manager at Akron Hydraulic. "Most equipment managers start drawing the line on repairs and parts when the cost approaches 50 percent of the equipment's value. This percentage can be expected to go up as the economy slows and capital expenditures tighten."

What control valves do
Control valves direct hydraulic pressure to where the operator needs it to go to do the job. These valves stop, start and direct fluid flow. Whenever a cylinder moves on an excavator boom or a hydraulic motor turns dozer tracks, control valves direct the speed and result of the work.

"Hydraulic pressure is a very powerful force, but it is not 'lsquo;intelligent,'" Langford said. "Oil will always follow the path of least resistance. This is why the tolerances inside a control valve are so tight - up to 0.0005 inch, which is one-tenth the width of a human hair."

Variable or fixed-displacement pumps generate the hydraulic fluid flow, and the flow resistance can sometimes be 3500 psi or more in a piece of heavy equipment. The oil needs to be held back at these pressures by a metal-to-metal fit inside the control valve, and any scoring on the spool will create a path of lower resistance. Oil will leave the spool as opposed to doing work. This causes the valve to be sluggish, cylinders to drift and spools to leak.

Spools and cartridges begin to leak when contaminants enter the hydraulic fluid, which is nearly impossible to prevent in the harsh environments construction equipment typically works in. To keep the equipment productive, the compromised components must be either repaired or replaced. Replacement control valves can sometimes run as high as $25,000 or more, and lead times can be months.

"Akron Hydraulic rebuilt a valve for us a few months ago. Replacement costs for a dual-function valve were sky-high, and I couldn't get it for weeks," said Dan Villars, maintenance manager at CT Taylor Company, Inc. "Akron Hydraulic turned it around quickly and I paid a fraction of what I would've paid replacing it. We reinstalled the valve on our Komatsu excavator, and it works like it did when it was new. We are very happy with the service we received."

Control valve rebuilding process
Akron Hydraulic's rebuilding process for control valves will restore them to like-new OEM performance for $600 to $900 per spool. For an eight-function valve, this can mean a savings of $20,000.

"The Akron Hydraulic rebuilding process is difficult and labor-intensive. It requires highly specialized machinery and machinists," Langford said. "Our process starts with disassembling the valve and inspecting the parts. Then we'll ground off the hard chrome on scored spools and replace the chrome and use micro-grinding to restore tolerances. We then cut oil grooves back into the spool after hard chroming is completed."

The cartridge or housing, if damaged, also goes through a similar micro-grinding process. Sometimes the spool needs to be rebuilt slightly larger if the cartridge needs to be honed. The valve is then reassembled with new seals, repainted and tested. Depending on complexity, this process takes three to four weeks, which is usually less than the lead time of a new valve.

This process can be benef

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