Installation Damage

Many O-ring failures can be directly attributed to Improper installation during assembly. In spite of its simple appearance, the O-ring is a precision device requiring care during installation. Some of the more frequent causes of O-ring failure due to careless handling are listed below


Damage to an O-ring during installation can occur when:
  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.
  2. Insufficient lead-in chamfer.
  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 however, some specific solutions which are listed below:
  1. Break all sharp edges on metal components.
  2. Allow 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 0-Lube or Parker Super 0-Lube if its use will not contaminate system.
  6. Double check O-ring to insure correct size and material.
  7. Be CAREFUL.
It is difficult to properly illustrate the many possible results of Installation Failure. However, below is an example of a common failure mode, the "Skiving" of the O-ring surface due to cutting by metal components. These cuts are usually very clean as if made with a very sharp knife. Another indication of bad installation will be small cuts or notches on the O-ring. In almost all cases, the damage will appear on the surface of the O-ring AWAY from the bottom of the O-ring groove.


Installation Damage
Installation DamageExample
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