Rotating Equipment

Mechanical Seal Failure

Mechanical seal failure occurs when a rotating-equipment seal can no longer control leakage between a rotating shaft and stationary housing.

What this term means in maintenance

Mechanical seal failure occurs when a rotating-equipment seal can no longer control leakage between a rotating shaft and stationary housing.

Common causes

Mechanical seals may fail because of:

  • Dry running
  • Misalignment
  • Shaft runout
  • Vibration
  • Incorrect installation
  • Wrong material
  • Contamination
  • Poor flush
  • Pressure or temperature
  • Pipe strain

Practical example

A pump seal leaks repeatedly because pipe strain distorts the casing and alignment.

Evidence

Review leakage pattern, seal faces, elastomers, operating conditions, flush system, alignment, and installation.

Corrective action

Replacing the seal may restore operation, but the underlying operating or mechanical condition must be addressed.

Common mistake

Treating every seal leak as normal wear hides installation, piping, process, and reliability problems.

Related maintenance terms

Keep exploring connected CMMS, reliability, and maintenance planning terms.

Mechanical Seal Failure FAQs

What causes mechanical seal failure?

Dry running, misalignment, vibration, wrong material, poor installation, flush problems, pressure, temperature, and pipe strain.

Is replacing the seal enough?

Only when the underlying cause has also been controlled.

What evidence should be reviewed?

Seal faces, elastomers, leakage, alignment, operating conditions, flush system, and installation.

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