I recently replaced a broken track spring. Mine are tensioned via grease pressure. I took images and intended to do a write-up but have been struggling for time. To do mine, I had to break the track. If you are also doing steering clutches, breaking the track makes that job easier. To break the track, I located the relevant pin and put it centre top, after which I removed the track plate to either side. I then fabricated a rough and ready punch support which bolted to the track. This enabled me to heat the track with the oxy, quickly turn it off and lay into the pin with a 14lb sledge. The previous time I broke the track, I split it at the rear of the machine but I needed an assistant to hold the driver punch (with a big pair of multigrips!). Working alone, having a rigid guide to align the punch made it much easier.
With regard to the track spring, one of mine was seriously broken when I bought the machine. I got away for quite a few years with simply welding it back together with low hydrogen (16TC) rods. Repair wouldn't last but was quick and easy. Replacing it was a reasonably big job. From memory, you should get change from $1k for the spring.