Are Your Face Seals Failing? Learn the Top 3 Causes and the Easy Solutions
At Grizzly, we often hear from our new customers that they’ve had past issues with mechanical face seals failing. To help you, we’ve gathered some information on the three main reasons face seals fail, and some tips to extend their life.
- Improper Installation
- Using the Incorrect Seal for Your Application
Before we get into why seals fail, it is important to know that mechanical face seals have two failure modes:
- Leakage of oil through the primary or secondary sealing
- Excess frictional torque present in the face seal
When a mechanical face seal fails, it does not pose any danger to the operator’s safety. However, once the oil is exhausted, external contaminants can enter the seal assembly and cause extensive damage to the internal components, such as differential gear in the case of axles.
1. Improper Installation
Because there are no credentials required to install mechanical face seals, improper technique often causes premature seal failure. During installation, errors as small as scratching the seal face can cause premature failure which is why a degree of experience is recommended. Following proper procedure and utilizing the correct installation tools will impact the life of your seals, as well as their effectiveness. To learn more about the correct installation procedure for SAP seals, click here.
When it comes to your face seals overheating, insufficient lubrication and excessive friction are the main culprits.
Face seals often become overheated when:
I. There is an insufficient amount of lubrication present to dissipate the heat generated by the face seals. This can be caused by:
a) An increase in oil temperature due to another system component. When the temperature increases, oil viscosity decreases, leading to the degradation of oil lubrication.
b) Improper selection of lubricating oil.
II. Excessive friction generated by the face seals. This can be caused by:
a) Scratches or scoring on the seal surface during installation. Scratches/scoring increases the amount of frictional heat generated.
b) Excess O-Ring Compression increases the face-load on the seal faces, which then increases the friction generated.
c) Improper Surface Finish on the face seals also increases the friction generated.
3. Using the Incorrect Seal for your Application
When it comes to mechanical face seals, the general rule is that they are expected to work for 10,000 hours for steel and 25,000 hours for cast. Both steel and cast materials have rated higher in some applications. If the seal fails before this time with no apparent cause, then the seal either has a manufacturing defect or you have a case off wrong seal for application on your hands. If you find yourself in this situation, contact a Grizzly application engineer or sales representative. An application engineer will be able to diagnose the problem and our knowledgeable sales reps will be able to offer you some solutions.
Click here for a great resource to guide you through the material identification and measuring processes.