Damage to the sleeve or shaft


Grooves or pits at the seal dynamic elastomer location.

  • Fretting.
  • Concentrated cell corrosion.
  • The rubber bellows did not vulcanize to the shaft/ sleeve.
  • The set-screws slipped on a hardened shaft or were not tightened properly. The seal faces stuck together causing the shaft to rotate inside the static elastomer.
  • Salt-water applications are particularly troublesome when a static elastomer or clamp is attached to the shaft. Pitting caused by the chlorides and the low pH of salt water are the main problems.

Rubbing at the wear ring location.

  • The pump is running off of its best efficiency point (BEP)
  • The shaft is bending.
  • Bad bearings.
  • Excessive temperature causing a thermal growth.
  • High temperature applications require a “center line pump design.
  • Sleeve is not concentric with the shaft, or the seal with the sleeve.
  • Bent shaft.
  • Unbalanced impeller or rotating assembly.
  • Pipe strain.
  • Misalignment between the pump and its driver



  • On February 18, 2018