Check your hoses if you buy replacements!
I sold my TATA to a local buyer, and a few months later I found a couple cans of R12 so I got together with him to charge the a/c. After a little fudging with the can tap (those things are nowhere near as easy to use as a can of R134a!), we got a couple cans in and it started cooling - until the hose blew out where it had been rubbing on the passenger side fender brace.
He bought a replacement hose from classic industries and installed it last week, so I drove up over the weekend with my vacuum pump and gauges. First thing we noticed was no more high side port on the muffler coming off the compressor. OK, we'll charge through the low side only. The system seemed to take forever to suck a can in, and it wasn't cooling at all; if anything, it seemed like hot air coming out the vents.
After getting 3 cans in and still no cooling, we laid the old hose out next to the new one and noticed that the routing is opposite - we were sending hot gas to the evaporator! He's going to get with the vendor to find out what happened and if they have the correct hose manifold, and we'll try it again.