Water pump bearings

Achieving Longer Service Life Through Resistance to Heat and Water

Water pump bearings are used in the water pump that circulates cooling water for the car's engine. JTEKT's bearings provide a longer service life thanks to their higher sealing performance and grease with excellent heat resistance and water resistance.

Functions Required of Bearings
and the Water Pump Structure

Water pump bearings are used in the car's water pump. A shaft appropriate to the inner ring is installed, and that shaft is longer than the width dimensions of the outer ring. To the larger-diameter side of the shaft is attached the driving pulley, while the impeller is attached to the small-diameter side.

What Are Water Pump Bearings?


Water pump bearings are sealed double-row bearings with wide spacing between the two rows of rolling elements.
There is a ball-ball type consisting of only balls and a ball-roller type consisting of a ball and a roller.
Standard products have a keyway (groove) in the center of the outside surface of the outer ring for a wire (clip) to prevent the water pump bearing from coming off.

Ball-ball type

Ball-roller type


  • 1.The profile of stepped shafts does not damage the shaft even if a large amount of force is applied from the belt.
  • 2.A highly effective seal is used to prevent leakage of filled grease and prevent cooling water that leaks out from the mechanical seal from entering the bearing. Some use a highly-sealed triple-lip seal to further enhance the prevention of cooling water from entering.
  • 3.The grease used has excellent durability in high-speed rotation, high-temperature, and mixed-water conditions, and the sealing material used has excellent compatibility with cooling water.

Standard seal structure

Highly sealed triple-seal structure

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Repair Products

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Feel free to let JTEKT know about your problems and requests,
whether it’s how to deal with breakdowns or other troubles, or switching over from another company’s product.

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