621G and 627G Wheel Tractor-Scrapers Machine Systems Caterpillar

Removal Procedure

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Pressurized air can cause personal injury. The air supply lines are pressurized to 830 kPa (120 psi). Purge the air from the system before performing any maintenance to the air system.

Note: Put identification marks on all hoses, wires, and tubes for installation purposes. Plug hoses and tubes. This helps to prevent fluid loss and this helps to keep contaminants from entering the system.

1. Park the machine on a hard, level surface. Lower the scraper bowl to the ground and engage the parking brake. Chock the wheels in order to prevent the machine from moving.

2. Purge the air from the air tanks. The air tank valves are located on the left side of the cab.

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3. Remove bolts (1) that secure access plate (2) to the machine. Open the access plate.

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4. Disconnect five tube assemblies (3) from air control valve (4) .

5. Disconnect three harness assemblies (5) from air control valve (4) .

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6. Remove bolts (6) from air control valve (4). Remove air control valve (4) .

Installation Procedure

Note: Clean all parts and inspect all parts. If any parts are worn or damaged use new parts for replacement.

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1. Position air control valve (4). Install bolts (6) that secure air control valve (4) onto the machine.

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2. Connect three harness assemblies (5) .

3. Connect five tube assemblies (3) to air control valve (4) .

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Illustration 6	g01019761

4. Close access plate (2). Install bolts (1) .