transmission clutch wd 45

I have replaced 3 driven discs + 2 center pressure plates 3 new retainer springs . When  I put it together and set the clutch up out of the tractor by adding the shims to the retainer washer of .140 press down by hand and measure all 3 gaps where the bolt holes are I come up with measurments of .160,.204 and.180  take out the .140 shims like the book says and add the rest of the parts pressure ring ,washer and retainer springs add shims in the correct 3 areas tighten bolts put pressure ring on ,But then i have to dissengage the clutch to line up the driven discs inside housing, there is alot of pressure there I can't get it to dissengage. Am I doing something wrong please and to information for me to check out or is this normal if so how do I dissengage clutch?

When using a 3-disc clutch, there is a shim stack AND a metal spacer shaped just like the shim stack at each of the three locations. In other words, the metal spacer is almost like having two shim stacks at each of three locations. Two disc clutches do not use this metal spacer/shim. Also make sure the clutch discs a installed so the hubs don't rub against each other.....center disc hub is the odd one.

yes I stand on the hub and it barely even moves is that correct or is somting wrong,it is a 3 disc system. I'm trying to disengage to check clearance between plates it feels like it's to tight?