My father-in-law and I had to rebuild my A/C system again. The gaskets on the back of my HR-6 compressor were shot, and blew out a substantial amount of R-12.
I wanted to use the 3 cans of Freeze 12 I had in my garage. We evacuated the system, and attempted to charge it with the Freeze 12. One of the gauges had a bad seal and leaked out over a can of Freeze 12. This led to another dilemma: order 4 cans of R12a, or convert the system to R134a. When we rebuilt the A/C system 3 years ago, we used oil compatible with both systems. We went with converting it to 134a to make it easier to work on in the future. After we got everything buttoned up, we discovered that the air was cold but not blowing hard. I replaced the blower motor ($30). Still didn't accomplish much. We pulled the blower motor off and discovered that there was no recirculate A/C setting. The air was being drawn from the passenger side cowl, and there was no cabin air circulating through the blower motor. This discovery led to a few major engineering projects and a couple trips to Home Despot. We installed a 4" x 6' flex dryer vent hose inside the blower motor, and ran it to the passenger side kick plate. This only solved half the problems. We hooked the vacuum lines up to a vacuum source, ran temporary power, and tested the blower motor. It still wasn't blowing a lot of air. We took the dash apart. It turns out the the geniuses that installed the ducts in the dash couldn't get the ducts to fit together in the center of the dash. They slapped a couple of strips of fabric duct tape to close the 3/8" gap between the upper and lower sections. My father-in-law ripped the duct tape off, installed some foam tape and screws to secure the ducts together, and sealed the edges with foil duct tape. He also discovered that the dampers inside the ducts were either hooked up incorrectly, or not hooked up at all. He figured out the correct duct positions and got it working!!