621H, 623H and 627H Wheel Tractor-Scrapers Machine Systems Caterpillar

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Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil can penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks.

A visual inspection of the machine is the first step in diagnosing a problem. Complete the visual inspections before you perform any operation checks. Perform the following visual checks:

1. Check all fluid levels.

2. Look for air in the oil that is in the tank. Look for air immediately after the machine is stopped. Use a clear container to get a sample of the oil. Look for air bubbles in the oil that is in the bottle.

3. Check for cracks in the hoses or check for wear in the hoses.

4. Check for cracks in the lines or check for wear in the lines.

5. Check for flow restrictions such as sharp bends, incorrectly installed clamps, damaged hoses and damaged lines.

6. Check for loose fluid and electrical connections.

7. Check for damage to components.