Bearings

Section 6.7 Wiping

Section 6.7
Wiping

Section 6.7.1
Appearance

The bearing surface is severely gouged and distorted. Discoloration of the surface may also be present. The surface also has a colored streaking appearance. See Figure "Example of Bearing Wiping"

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Figure 1. Example of Bearing Wiping

Section 6.7.2
Damage

Wiping occurs when the bearing and journal have come into direct contact with each other from lack of oil film. Wiping produces high heat from friction between the two surfaces. This condition may be from fuel or coolant diluting of lubricating oil. See Figure "Illustration of Oil Film Levels" .‪

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Figure 2. Illustration of Oil Film Levels

Overloading can cause wiping. Wiping can also occur when the oil galleries become plugged from foreign debris. ‪

Section 6.7.3
Possible Causes

There are several possible causes for the damage: ‪

  1. Dilution of the oil by fuel or coolant.
  2. Failure to change the lubricating oil within the recommended schedule.
  3. Lack of oil pressure from pump, bearing clearance, or plugged oil galleries.
  4. Overloading of the engine.

Section 6.7.4
Recommendation

The recommended maintenance procedures after finding corrosion are:‪

  1. Replace bearings.
  2. Change the lubricating oil and fix leaks in coolant of fuel.
  3. Use recommended maintenance practices.
  4. Clean and flush all oil galleries.


Bearings Technician's Guide - 7SE448
Generated on 10-13-2008

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