KIT-ENGINE OVERHAUL 3851748 - Caterpillar

Introduction
This special instruction provides necessary information that is needed to repair plastic fuel tanks. Repair of black plastic fuel tanks requires a flame treating of the damaged area. Other plastic fuel tanks do not require a flame treating of the damaged area.Required Parts
Table 1
Required Parts for 1U-8118 Repair Kit
Part Number Description Quantity
1U-8119 Sealant 1
1U-8120 Cloth 305 mm × 305 mm (12 inch × 12 inch) 1 Repair Procedure
Drain all the fuel from the tank.Note: If the fuel tank is not black polyethylene, the tank can be drained to a level that is below the damaged area. The level should be low enough that the fuel will not splash into the damaged area during repair. Fuel should not be in the damaged area for a minimum of 10 hours after repair.Note: Proceed to step 3 if the tank is not black.
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".
If the tank is black, the tank should be prepared for safe welding.Note: An empty fuel tank cannot be cleaned sufficiently to ensure that all the flammable vapors have been removed. Vapors remain even after cleaning with steam, or washing with a caustic solution. The tank can be filled with carbon dioxide, or the tank can be filled with water.
Fill the tank with carbon dioxide.To fill the tank with carbon dioxide, plug all the openings in the tank except the filler hole. Fill the tank with carbon dioxide from a CO2 fire extinguisher. Then, cover the filler hole to keep the carbon dioxide in the tank. After filling the tank with carbon dioxide, the repairs can be made by using the proper welding practices.
Fill the tank with water.To fill the tank with water, plug all the openings in the tank except the filler hole. Fill the tank with water. Fill the tank to the top of the filler hole. The tank should be kept full to ensure that there is no space for the collection of vapors. After filling the tank with water, the repairs can be made by using the proper welding practices.
Lightly sand the damaged area. Wash the damaged area with warm water.Note: Proceed to step 5 if the tank is not black.
Black tanks require a flame treating. Treat at least a 101.6 mm (4 inch) band around the damaged area.
Use a butane hand torch that is equipped with a needle burner. Allow the torch to warm up for two or three minutes.
Rapidly brush the flame across the damaged spot and the surrounding area. Use the portion of the flame that is 12.7 mm (0.5 inch) beyond the visible blue tip.Care must be taken to prevent the