Regarding the expander and sizer for the piston seal, are you saying they are not necessary? I am on the fence of DIYing my FEL and backhoe cylinder rebuilds. I have the means to do it, but I don't have any of the necessary tools for the piston seal installation like what I have seen used in some Youtube videos. Here is an example of an expander/installation and re-size tool that one video references. I can't imagine an hydraulic shop has these specialty tools for every single size piston that they may have come into the shop?
What is your approach to installing the piston seals without the "proper" tools?
The first cylinder I did, the only special tool I bought was a face spanner. I could have used a pipe wrench to remove the cap.
I wrestled the rod seal in with small screwdrivers etc., but I could see the potential for ruining a seal, especially with the smaller rods. So I ordered the 3 pc set of seal installers. They work pretty well.
I just used several small, smooth screwdrivers to install the rod seal parts. Some are square cup plastic (teflon?) and kind of hard. You can soften them in hot water if needed. They recover slowly and you don't want to stretch them more than necessary. The cylinders I've worked on had a lot of taper on the bore, so it was easy to get the piston back in.
The piston nut is pretty tight. I used a 3/4 drive bar and a short cheater on it. You may be ok abusing your 1/2" breaker if that's all you have. Take pictures to make sure you get them back on in order. Work clean.