Sinar stuff is easily refurbishable, and by and large, the parts are available for the F and P series cameras. Remember, though, that if you order parts from Sinar-Bron, from their perspective, it's still a $10,000 camera, so those replacement levels, nylon gear tracks and bushings aren't cheap.

I was lucky to buy my 8x10" P from a working studio that had regular visits from a Sinar rep and kept everything in good shape. I had to replace a couple of levels, but most of the nylon parts were of the P2 era (and for the most part, P and P2 parts are the same, aside from issues of metering vs. non-metering backs and such).