Wheel Bearing Wear - Straight Bearing
Wheel Bearing Wear - Rear Drive Axle: (Straight)Straight Roller Bearing Diagnosis
Consider the following factors when diagnosing a bearing condition:
^ Note the general condition of all parts during disassembly and inspection.
^ Classify the failure with the aid of the illustrations.
^ Determine the cause.
^ Make all repairs following recommended procedures.
Wear (Minor)
Light pattern on races and rollers can be caused by fine abrasives. Clean all of the parts including the housings. Check the seals. Replace the bearings if rough or noisy. Replace the shaft if damaged.
Wear (Major)
Heavy pattern on races and rollers can be caused by fine abrasives. Clean all of the parts including the housing. Check the seals. Replace the bearings if rough or noisy. Replace the shaft if damaged.
Brinelling
Surface indentations in the raceway can be caused by roll either under impact loading or vibration while the bearing is not rotating. Replace the bearing if rough or noisy. Replace the shaft if damaged.
Indentations
Surface depressions on race and rollers can be caused by hard particles of foreign material. Clean all of the parts, including the housing. Check the seals. Replace the bearings if rough or noisy. Replace the shaft if damaged.
Single Edge Pitting
Flaking of surface metal results from fatigue, usually at one edge of race and rollers. Replace the bearing. Clean all related parts. Replace the shaft if damaged.
Double Edge Pitting
Flaking of surface metal results from fatigue, usually at both edges of the race and rollers. Replace the bearing. Clean all related parts. Replace the shaft if damaged.
Misalignment
Outer misalignment due to a foreign object. Replace the bearing. Ensure races are properly seated. Replace the shaft if the bearing operating surface is damaged.
Frettage
Corrosion set up by a small relative movement of parts with no lubrication. Replace the bearing. Clean all the relative parts. Check the seals. Check for proper fit and lubrication. Replace the shaft if damaged.
Smears
Smearing of metal due to slippage. Slippage can be caused by poor fits, lack of lubrication, overheating, overloads or handling damage. Replace the bearing. Clean all the related parts. Check for proper fit and lubrication.
Rear Axle Lubricant Leak Diagnosis
Rear axle lubricant leaks can occur at the following locations:
^ Axle tube to differential carrier housing joint
^ Axle shaft oil seal
^ Axle housing porosity
^ Differential housing cover gasket
^ Drain plug
^ Fill plug
^ Pinion yoke oil seal
^ Vent tube
Determining the Cause
While most rear axle leaks may be easy to find, determining the cause may not be. A thorough inspection of the area around the leak may assist in determining the cause of the leak.
Oil Seals
Lubricant leaks from a oil seal may be caused by any of the following:
^ An improperly installed seal
^ A distorted seal
^ A worn seal
^ A worn shaft
^ A brittle seal lip
^ A hardened seal lip
To determine the actual cause of the leak, clean the area around the leak. Observe the area of the leak and determine the if the seal or another component is causing the leak. A worn seal surface will cause a leak at the sealing lip while a misaligned seal or a seal installed into a housing with an excessive bore will cause the seal to leak at the outside surface of the seal. Hardened or cracked seal lips usually indicate the axle is operating beyond the normal temperature limits for the axle. A seal whose sealing surface has been nicked or cut may indicate that the shaft has a rough, burred, or gouged surface and will need to be inspected before the seal can be replaced.
Gaskets
A leak at a gasket is usually caused by a poor fit of the components on each side of the gasket surface. Inspect each component for distortion and for nicks or gouges that may prohibit the gasket from sealing properly.
Rear Axle Housing
Rear axle housing lubricant leaks usually occur at the following locations:
^ Drain Plug
^ Fill Plug
Drain and fill plug leaks are usually caused by a loose plug. These leaks can by repaired by either tightening the plug or by using an approved sealer on the threads on the plug.Other leaks such as axle tube to differential carrier housing or porosity leaks require the replacement of the rear axle housing.