A guide to why your Oil Seal / Rotary Shaft Seal may fail

There are two parts an Oil Seal / Rotary Shaft Seal where leakage can occur:

1. The interface between housing bore and seal O.D
2. Between the seal lip and shaft

The following Oil Seal Failure Checklist shows the causes of failure and the means of prevention. 

SYMPTOM: Oil Seal moves in axial direction along the shaft

SYMPTOM: Seal installed in declining condition

SYMPTOM: The deformation of the metal case

SYMPTOM: The damage on the case O.D

Use correct installation tool

SYMPTOM: Lip worn seriously

SYMPTOM: Lip partially worn

SYMPTOM: Lip partially worn

CAUSE: Seal misaligned in housing

RECOMMENDED ACTION: Ensure housing bore is correct
Use correct installation tool

SYMPTOM: Lip hardened worn and cracked
CAUSE: High temperature / shaft rotation speed / pressure
RECOMMENDED ACTION: Select a suitable compound type
Supply sufficient lubricant

SYMPTOM: Lip material swollen
CAUSE: Incorrect compound selection
RECOMMENDED ACTION: Select the correct compound

SYMPTOM: Lip scratched
CAUSE: The shaft surface is not smooth
Scratch caused by incorrect installation tool
RECOMMENDED ACTION: Let all the lip configuration clear Install seal correctly

SYMPTOM: Lip turning out
CAUSE: Incorrect installation
Inner pressure too high
RECOMMENDED ACTION: Lubricate the lip and shaft before installation
Use pressure type seal

SYMPTOM: Crack on the base of flex section
CAUSE: Inner pressure too high
Sudden pressure strike on the flex section
RECOMMENDED ACTION: Use high-pressure type seals

SYMPTOM: Spring dislodged from spring groove
CAUSE: Shaft chamfer is incorrect
Incorrect installation
The retainer lip is too short
RECOMMENDED ACTION: Finish the shaft chamfer and lubricate the shaft before installation
Be careful while installing
Change the seal design