I wanted to post an update to this thread in case someone with an old dozer like mine stumbles across it while doing their angle cylinders and is having trouble trying to get their piston apart to replace a broken spring.
My OCD would not allow me to put the piston with the bad spring back in the cylinder since I will be selling this dozer when I'm done using it for my projects. I wasted several weeks ordering aftermarket pistons from a few different sources including eBay and Amazon and some other place, only to find out each time after ordering (and wasting a few days thinking it was on the way to me) that each place did not have the piston in stock and had no idea when any would come in.
I did not want to spend $600+ on a new Cat piston but I did discover that Cat offered one of their Yellowmark parts for $350 or so. Feeling like I had nothing to lose anyway I got a little more aggressive with my efforts to get the original piston apart. I spent several hours working on it. I won't bore you with the details, but I'll sum it by saying I got it apart only to find out that one of the four parts I needed to rebuild my original piston (Cat calls it a spacer but really it's the sleeve that holds the valves and spring into the piston) is no longer available from Cat., I could not find an aftermarket source for that part either. The other three parts 2-valve rods and 1-spring are still available from Cat if you are somehow lucky enough to get your piston apart without destroying the "spacer". In my case I ended up having to order the Yellowmark part from Cat. Good luck to you if you are resealing your angle cylinders and find out that the relief valves are bad. T
