I'm doing work on my 1952 d2 5U main clutch assembly and specially having an issue with the main clutch brake. The tractor is split atm.
I'm having trouble getting the spider assembly to interact with the actual clutch brake discs. 
I have the spacer tube indexed with the clutch spider and it still won't reach the clutch brake discs. It's nearly 1/4inch from touching the brake discs when I push the control lever all the way forward.
I have a new clutch disc installed and I have the pressure plates surface grinded. 
Someone suggested that my main clutch disc is too thick? Anyone have any additional thoughts?
I was thinking I could put some spacers behind the clutch disc brake plates and that would solve my issue.
I'll post a video shortly. Thanks, Jonathan

Video

I added some washers to the one clutch brake retainer plate to mimic the spacer I was thinking of making.

drive.google.com/file/d/19REk5syYlmOVqR0...XUQ/view?usp=sharing

last night I ended up installing my old thinner main clutch disc in the assembly, I adjusted it(what a pain) and I'm really liking the lever engagement pressure and throw distance. The over center engagement feels great. It's still not traveling far enough to engage with the clutch brakes, when I push the lever all the way forward. I'm at a loss what the issue could be. But I feel like adding the spacer plate would remedy this issue.

I noticed if I push the lever foward to engage the clutch brake and I simultaneously spin the pressure plate, there is some sort of resistance, just like the brake is enagaged, but they clearly aren't touching. What the heck is going on? I don't have 3 hands to take a video of this. Hope this makes sense the way I described it.

Are you sure that the brass collar is in correctly

thanks, I found this diagram in my servicemens reference book.
drive.google.com/file/d/1jnVjdmZ7HLlIznz...vfd/view?usp=sharing

I checked numbers 5 and 7 for correct clearance last night. The top didn't have any clearance, so that's part of my problem. Still trying to fix this. Will report back soon if that resolves my issue.

Hi Team,
something I have encountered is that the vertical actuation shaft woodruff keys have been aligned to the split in either lever instead of the key slot in the relevant lever--this puts the levers out of phase and so can cause reduced clutch engagement motion in one direction or the other.
Another lost motion area to check is to the top vert. shaft and its bushing if fitted--if not then the shaft bore in the top case needs machining to take a suitable bush and even a dirt seal.
Also check if the upper vertical shaft lever is not fouling the floor plate due to the shaft/bush wear described above.

Cheers,
Eddie B.

Hi, I adjusted the yoke and collar clearance last night per the servicemens manual. The assembly still won't pivot far enough to touch the clutch brake plates. Previously I had a local machine shop make a bronze bushing for the top vertical shaft, so there is no play with that piece. I still can't figure out my issue. There has to be something I'm missing with this.

Would any additional video of this help? If so, what do you want to see exactly? thanks for your help so far.

I confirmed the keys for the lever and yoke forks are in the machined slots, and not in the splits where the bolts are tightened.

Can that vertical shaft go in upside down, and did you remove it to fit the new bronze bush?