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Installation Damage

Many O-ring failures can be directly attributed to improper installation. In spite of its simple appearance, the O-ring is a precision device requiring care during installation. Leakage will often be instantaneous. Installation damage is generally evidenced by a clean line in the seal, often in a pattern consistent with the hardware.

Some of the more frequent causes of O-ring failure due to careless handling are:

1. There are sharp corners on mating metal components such as the O-ring gland or threads over which the O-ring must pass during assembly.   Picture shown of O-ring with slice due to a thread cutting the O-ring

2. Insufficient lead-in chamfer. See diagram for recommendation:


3. Blind grooves in multi-port valves.

4. Oversize O-ring on piston seal application.

5. Undersize O-ring on rod application.

6. O-ring twisted/pinched during installation.

7. O-ring not properly lubricated before installation.

8. O-ring dirty upon installation.

9. O-ring gland and/or other surfaces over which O-ring must pass during assembly contaminated with metal particles.

10. General Carelessness.


Probably the best way to prevent damage to O-rings during installation is the use of good old-fashioned “Common Sense.” There are some specific solutions which are listed below:

1. Break all sharp edges on metal components.

2. Provide a 20° lead-in chamfer.

3. Check all components for cleanliness before installation.

4. Tape all threads over which the O-ring will pass.

5. Use an O-ring lubricant such as Parker O-Lube or Parker Super O-Lube if its use will not contaminate system.

6. Double check O-ring to ensure correct size and material.


Parker Hannifin
O-Ring & Engineered Seals
2360 Palumbo Drive
Lexington, KY 40509
Ph: 859-269-2351
Fax: 859-335-5128