I have the FXDXT (T-Sport) with a leaky fork seal. The forks have the adjusters on them and the manual says to replace seals I need to, after unscrewing the top cap, remove the springs with a special harley tool. Then I can remove the bottom bolt to pull the sliders off. Then to reassemble, to reset the adjusters and then attach the springs again. Why can I just uncap, drain, unscrew bottom bolt remove sliders, replace seal and reassemble without removing the spring from the top cap?

 

I've never done it, as my FXDXT never needed seals and I passed the manual on with the bike. My guess is the springs are pre-loaded in some way, hence the procedure you mention. It is our duty to look for short cuts, but that may not be one of them!