Rebuilt one of these last week, took a few pics.
The animal in question
With the controls off and lower piston out
Top piston, seals and spacers out, ready to go back in. I'll explain my use of the rag in a bit
The upper and lower pistons, upper and lower seal and spacer stacks
These are the "stuffer" tools used to "stuff" the seals and spacers into the head.
The seals go on the inside like this
You the shove the tool into the head until it bottoms out, push the middle of the tool in while pulling the tool out, setting the seal.
The spacers go in on the other end of the tool:
Push it in until it bottoms out then pull back on the middle of the tool leaving the spacer in place.
Here is the top one in the head. I put the pen marks on the tool to help me know if I'm in bottomed out.
The rag- The first time I ever did one of these, I was told no special tools were needed. Some people make their own tools to install the seals and spacers. I'm not good enough to do that. The upper piston is a booger. If you don't have the seals set where they belong, they can fall down through the head into the mineral, never to be heard from again. I stuff the rag into the lower piston hole so if I don't have a seal set right it will fall into the rag and I can dig it out. When I do the lower seals and spacers, I take a piece of solder and immediately stick it through the hole when I pull the tool out in case one tries to pop out when I'm not looking.