SWITCH IND & 3443269 - Caterpillar

Introduction
Reports from the field indicate that hydraulic oil tanks leak from cracks and pin holes.Problem
There are multiple locations on the hydraulic oil tank for the cracks and pin holes.Solution
If the hydraulic oil tank leaks from cracks or pin holes, you have two options. As required, you can repair the hydraulic oil tank by rewelding the existing welds on the entire hydraulic oil tank or you can replace the hydraulic oil tank. Use the repair procedure that follows, if the hydraulic oil tank is rewelded.Repair Procedure for Hydraulic Oil Tanks
ReferenceRefer to Special Instruction, REHS1841, "General Welding Procedures" for additional information.Welding on Hydraulic Oil Tanks
Personal injury or death can result from an explosion.Applying heat to a tank which has held flammable liquids, even when empty, can result in residual flammable liquid or vapor igniting with explosive force.Do not weld or flame cut on any tank that has held flammable liquid without taking the proper precautions such as filling the tank with either carbon dioxide or water.Please refer to Special Instruction, REHS1841, "General Welding Procedures".
Personal injury can result from working with cleaning solvent.Because of the volatile nature of many cleaning solvents, extreme caution must be exercised when using them. If unsure about a particular cleaning fluid, refer to the manufacturer's instructions and directions.Always wear protective clothing and eye protection when working with cleaning solvents.
Personal injury can result from flame cutting or welding on painted areas.The effect of gasses from burned paint is a hazard to the person doing the cutting or welding.Do not flame cut or weld on painted areas.
Personal injury or death can result from fumes, gases and ultraviolet rays from the weld arc.Welding can cause fumes, burn skin and produce ultraviolet rays.Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing area. Wear eye, ear and body protection before working.Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can cause death.Read and understand the manufacturer's instructions and your employer's safety practices. Do not touch live electrical parts.See "American National Standard Z49.1, Safety in Welding and Cutting" published by the American Welding Society.American Welding Society
2501 N.W. 7th Street
Miami, Florida 33125
See "OSHA Safety and Health Standards, 29 CFR 1910", available from U.S. Department of Labor.U.S. Department of Labor
Washington, D.C. 20210
Do not weld on a closed hydraulic oil tank.Preparing the Hydraulic Oil Tank for Welding
Drain the hydraulic oil from the tank into a clean container. If the hydraulic oil is kept clean you can reuse the hydraulic oil. Refer to the Operation and Maintenance Manual that is appropriate for your machine for the proper procedure.
Remove the hydraulic oil tank from the machine. Then place the tank in a horizontal position. Refer to the Disassembly and Assembly manual that is appropriate for your machine for the proper procedure.
Remove the top cover assembly from the tank in order