If you have a caliper (measuring device), you can measure from the end of the shaft to a reference point on the outer hub. Take a starting measurement, then take another measurement after you move it a bit.

 

Haha ahh thanks sir, I was thinking more like a feeler gauge. Will have to try this one soon.

 

You could do it with a feeler gauge as well. Just depends on what you have available. With a feeler gauge, you have to make sure that your points of reference are remaining consistent.

 

i to work in the a/c reman. take the belt off an check if ur bearing is good. the bearing my b going out. but if ur bearing is good just get that tool to pull the hub out a little an u should b good to go. just make sure that it still ingages after u pull it out.

 

Use a shim gage to set air gap to .020" air gap is distance between pulley and clutch armature plate--about the thickness of a business card..