Axial Vibration Gap Voltage

Your mechanical crew should be able to tell you, otherwise they are not competent to do the work. They should not do work if they do not know how to repair to the design spec or original condition.

I do not see the voltmeter accessory :)

- - for the gap voltage of thrust axial.

Picky, picky picky. Just substitute voltmeter for digital readout.

Or, substitute OP for one with common sense.

Calculating thrust is difficult as it depends on a myriad of dynamics such as fluid temperature, viscosity, type, quantity of solids, etc.

The pump manufacturer would be a good source for the information.

However after the initial setup I would suggest that you pick an unmovable reference point on the pump casing such as an edge of a seal where it contacts the shaft, mark the pump shaft, start the pump, load the pump to the maximum process conveying limit and mark the shaft at the same reference point.

Shut the pump down and measure the "actual" thrust movement of the pump for your application.

Do not forget to identify the prime mover thrust as well and take it into account when you do the setup.