On a somewhat unrelated note (I don't feel like starting another thread just yet), I re-assembled the lens just to see if I got the focus right and it seems bang on (at least at infinity). But when rotating the lens towards close focus (between 0.6-0.7m) i hear a click. Okay I thought it could be something loose, but when I turn it back towards infinity, as it passes that very same spot, I hear horrible crunching noise. It didn't take long to realize that a spring was interfering with the rear element. You can see it happening in the pic below.
It only happens when the depth of field lever thingy is pushed towards the left (when mounted on camera). The tension on the lever pulls the spring right into the path of the rear element when i try to focus it back towards infinity.
My first thought was that I re-assembled the helicoids incorrectly (and the rear element was pushing too far into the barrel causing the spring to pop in), but the infinity focus is working, so I assume everything else is accurate, and the elements are positioned where they are supposed to be.
What gives? I plan on disassembling the lens to properly grease, but I would like to know how to fix this as well.