First, we have nearly 20 feet of rubber hose that we're trying to seal freon inside. Only brand-new hoses and fittings will do this, and the hoses don't last long in any case- especially the ones that pass by the hot headers. Second, the York AC compressor is from the '50s, and its seals may not be up to sealing todays freon r-134a. Its quite heavy and at low speeds, its oriented such that it litarally shakes the car sideways. Most guys swap them for an aluminum Sankyo rotary. SAnkyo actually sells an adapter bracket to fit the old York brackets in our cars. Third, the dryer can in back deteriorates with age- inside is a cloth bag of dessicant meant for soaking up water in the system. The bags rot away in a few years and in any case, in a non-working system, the dessicant is alreadyy saturated with water. The compressor then pumps pieces of bag, dessicant grainss etc throughout the system, and theres a tiny filter screen in the 'in' arm of the expansion valve under the dash (pass. side). The screen plugs, pressure goes up and one of the ancient hoses blows. There are fixes for al this stuff; IMHO you're lucky the system worked at all. It undoubtably needs a thorough tune-up with all-new hoses etc. Some guys add an over-pressure Hoibbs wwitch to shut the system down if pressure exceeds a certain level, but if the filter is clear & the hoses are tight, all should be well. Of course, over 120 mph, it doesn't cool well....
