Grease Leak from Front Hub Bearings - keywords axle brake front knuckle rotor wheel
| Subject: | Grease Leak From Front Hub Bearings |
| Models: | 2004-2007 Cadillac Escalade Models |
| 2004-2007 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe |
| 2004-2007 GMC Sierra, Sierra Classic, Yukon and Yukon Denali Models |
| 2004-2007 Hummer H2 |
This PI is being updated to add models and years. Please discard PIT3078B.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
The factory grease fill of the bearing/hub assembly includes a greater amount of grease than required for adequate bearing lubrication throughout the life of the vehicle. A portion of the grease will purge through the self-venting bearing seals in the initial few thousand miles/kilometers and helps to form an additional barrier to block the ingress of contamination into the bearing. This additional barrier is called a "grease dam". This grease dam will form in the area near the bearing seal and will mix with outside dirt. In addition, grease may move radially outward from this area onto adjoining components.
Recommendation/Instructions:
Do not replace the bearing for grease purge. Furthermore, do not clean the purged grease from the area immediately on or adjacent to the seals because this grease provides additional protection. If desired, any grease that has migrated away from the immediate seal area can be wiped off.
The bearing should be replaced only if:
| • | The seals show visible damage |
| • | The bearing endplay is greater than 0.005" or 0.13mm |
| • | The bearing exhibits rough rotation |
| • | The bearing exhibits abnormal noise |
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
