despite anything currently wrong, does the boom have ALL new hoses within the last year or two? cost me $1300 to have ONE hose replaced last year when it blew, not a job you want to tackle yourself
id have to count but I believe it would be around $12K to replace all the hoses in my boom, each one is 53 feet long to be exact
that rotator fitting should be rebuildable with a $70 seal kit I believe, if that is leaking its a safe bet most or all the cylinders will also need re-packed soon, which isnt horrible to do but the main boom cylinder is extremely large and heavy, outrigger cylinders SUUUUCK, took me 4 days to get mine out when it started leaking and I had to have a machine shop make me new pins because I had to torch out the old ones, and needed a crane to put the outriggers back in after 2 months at the shop sitting on their shelf
maybe you will get luckier than me, but as soon as my truck has more hydraulic issues the boom is being scrapped, not worth the money to fix
inspect the truck, better yet have the seller get a boom inspection and write down everything wrong with it, if the rotator is it then get the truck, but id look at other trucks if it needs more hydraulic work, booms are much more complex than say an excavator, and since replacing hoses bridges insulation and its a "major repair" it is REQUIRED that you get a new annual inspection and dielectric test before it can go back to work, even if it passed one a week before the work
good luck, wish I had better input, this is just my experience, someone else will chime in soon enough im sure
