"A common problem with hydraulic cylinders is rust and pitting of the cylinder rods (Figure 1). If equipment that incorporates hydraulic cylinders is stored outside with the cylinder rods extended, the rods are exposed to weathering. Eventually, the rods will begin to show specks of rust that develop into pits. Once rusting and pitting occur, the rod will destroy the cylinder seal the next time it is activated. Once pitted, it is virtually impossible to restore a cylinder rod to an acceptably smooth condition through repolishing.
This problem of cylinder-rod pitting is most common with hydraulic cylinders on equipment that is both stored outside and seldom used or used only seasonally. If the hydraulic cylinders are operated every few days, the rods will always have a thin coating of oil that will provide protection, and rust will not start. Good examples are backhoes and bulldozers that are always stored out in the weather but are used almost daily.
The solution to this problem is to prevent rust and pitting. There are three ways to accomplish this..."