More than likely you will need a D.O.T. compatible bleed kit, Park Tool makes a really high quality one that I would recommend but it is possible Hayes makes one. However your local shop is beyond correct any of those old brakes are not worth your time and effort a cheap set of Shimano MT-200s are so much better and easier to get parts for and most shops will be fine working on them. Old outdated brakes that were not that exceptional back in the day don't get any better and seals can wear out and dry up and you could spend a lot of time bleeding and re-bleeding for it just to leak and have issues. I know keeping some parts going is great but old hydraulic brakes from the almost 30 years ago just aren't really worth the time, effort and expense. Yes it was a great brake back then when brakes weren't so good but now a cheap Shimano brake is pretty darn good and way better than some of the old brakes that could cost $100-400 back in the day and these are $40-60.