2009/04/27 Proper Long Term Storage of Caterpillar Products {0355, 1000, 7000} Caterpillar

ReferenceSpecial Instruction, SEHS9031, "Storage Procedure for AVSpare Products"

An increased occurrence of pitting in the chrome surface of hydraulic cylinder rods has been reported. The root cause for this increase in failure mode is incorrect machine preparation for long term storage.

It is important for all Cat dealers to inform your customers to reference Special Instruction, SEHS9031, "Storage Procedure for AVSpare Products" before the customer shuts down a machine for extended periods of time. Proper long term storage will extend the service life of your machine.

Illustration 1	g01889693
Example of surface pitting in the chrome finish of a hydraulic cylinder rod

Surface pitting in the chrome finish of a cylinder rod can be attributed to corrosion that is caused by improper preparation of the cylinder rod for long term storage. Refer to Illustration 1.

Illustration 2	g01889675
Example of naturally occurring cracks in the chrome surface

Illustration 3	g01889618
An example of the chrome surface of a cylinder rod after corrosion has attacked the base material.

When the chrome's surface is viewed with magnification, naturally occurring cracks are visible. If the cracks are not sealed properly, the cracks will allow a path for corrosion to attack the base metal of the cylinder rod. Refer to Illustration 2 and Illustration 3.