789B Off-Highway Truck Caterpillar

Hoist, Torque Converter and Brake Tank Suction Screen - Inspect, Clean and Replace

Usage:

789B 7EK

There are four suction screens on the tank for the hoist, the torque converter and the brakes. There are two return screens inside the tank for the hoist, the torque converter and the brakes. Clean all of the screens whenever there is a failure of brakes, torque converter, hoist cylinders or hoist pumps.

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Illustration 1	g00352692

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NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of all fluids according to local regulations and mandates.

Remove the tank drain plug. Install a 88 mm (3.50 inch) long NPT pipe nipple in order to open the internal drain valve. The outer diameter of the NPT pipe nipple should be 25.4 mm (1 inch). Drain the oil into a suitable container.
Note: Hand tighten the NPT pipe nipple. Do not use tools.

Remove the bolts from the cover on the front of the tank for the hoist, the torque converter and the brakes. Remove the cover.

Clean the debris from the bottom of the tank.

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Illustration 2	g00322724

Remove retaining nuts (1) from cover (2) . Remove the retaining nuts from the cover on the other side of the tank. Remove screens (3) . Discard screens (3) .

Install new screens (3) , new covers (2) and new retaining nuts (1) .

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Illustration 3	g00451056

Remove the suction lines.

Remove the suction screens from the tank for the hoist, the torque converter and the brakes.

Wash the suction screens in clean, nonflammable solvent.

Install the clean suction screens, the hoses and clean retaining bolts.

Clean the cover for the front of tank for the hoist, the torque converter and the brakes in clean, nonflammable solvent. Inspect the cover gasket. If the gasket is damaged, replace the gasket.

Install the cover to the front of the tank.

Fill the tank for the hoist, the torque converter and the brakes. Refer to Operation and Maintenance Manual, "Lubricant Viscosities". Refer to Operation and Maintenance Manual, "Refill Capacities" .

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Illustration 4	g00436821

Use the engine shutdown control to prevent the engine from starting. Crank the engine for approximately 15 seconds. The oil level will decrease as oil fills the system.

Add oil to the tank in order to raise the oil level to the safe starting range.

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Illustration 5	g00441963

Repeat Step 13 and Step 14 until the oil stabilizes in the FULL mark in the sight gauge.

Lower the guard on the engine shutdown control. Start the engine. Run the engine at low idle. Inspect the machine for oil leaks. Make necessary repairs.