This video walks through the steps to adjust and set end play on a typical vertical hollow shaft pump motor.

Vertical hollow-shaft motors present some unique reassembly challenges, one of which is setting end play. Here's a tip that applies to assembly of vertical hollow-shaft motors in the 320 to 440 frame drip-proof enclosures with grease lubricated lower guide bearings and oil-lubricated upper thrust bearings.

There are applications where the end float inherent to a sleeve bearing machine is not desirable, and some means of limiting the axial movement is needed. This is usually accomplished by selecting an appropriate coupling and relying on the driven equipment to prevent axial movement of the motor shaft. 

The gear-hub style of coupling can be end-float limited by installing a “hockey-puck” spacer. The grid-style coupling can be limited by spacers inserted on both sides. 

Regardless of coupling style, unless the driven equipment has some internal means to limit end float, there are circumstances where some external means of preventing axial movement is needed.

An electric motor must have room for thermal expansion of the shaft, or bearing life will be severely reduced. The endplay of a ball bearing motor plays an important role in bearing life.