Dollar-for-dollar, piston rod seals may have the toughest job of any component in a hydraulic system. They are one of the least expensive parts in the system, yet they are expected to keep oil in the cylinder within a wide range of temperatures and pressures — with plenty of shock and pressure pulsations thrown in for good measure — while also keeping contaminants out.

Protect piston rodsNo, they don’t cost much, but when one goes bad, everyone knows because oil leaking from a cylinder won’t go unnoticed. And having to replace a seal can be quite costly both in labor to replace the seal and lost productivity from downtime.

Avoiding contamination

A primary cause of premature seal failure is contamination. An oil film on the piston rod lubricates the seal so it can achieve maximum life. But that same oil film can attract dirt and even cause it to stick. When the rod retracts, this dirt can be drawn past the seal and probably cause minor damage. But when this damage occurs repeatedly, the cumulative damage will ultimately result in leakage. And the more abrasive the contaminants, the more rapid the wear. Plus, once contaminants get past the seal, they can enter the hydraulic system to cause even more harm.

Therefore, it’s in everyone’s best interest to ensure the integrity of seals. The way to do this is to keep contaminants away from the piston rod. But this isn’t always practical or even possible when the cylinder must operate in areas continually exposed to mud, dirt, and other contaminants. You usually can’t relocate the cylinder to a cleaner area, so the only other choice is to keep contamination away from the piston rod. This can be done by shielding the rod from the surrounding environment with a rod cover, also known as a boot or bellows.

Custom-engineered protective boots for cylinder rods are available for machine tools, mobile equipment, and other machinery to reduce or eliminate rod scoring, prevent nicking, and extend seal life by keeping chips, abrasive particles, and other potentially harmful substances away from the rod. Manufactured from coated fabric, Gortite rod boots provide millions of trouble-free operations in temperature ranges of –40° to 220° F. Boots made of other materials and designs can be provided for virtually any application..

For more information, contact A & A Mfg. Co. Inc., New Berlin, Wis., at (262) 786-1500, or visit www.gortite.com.