This is the second attempt to get my 1984 F150 AC system converted from R12 to R134. After the first attempt my compressor was cycling 4 sec. on 25 seconds off. So nothing was getting cool. Adjusting the low-pressure switch did not help. My ford spec book diagnostic chart suggested that the condenser fixed orifice might be restricted. I had the system evacuated again and removed a part that was in the condenser output line. It was a flanged long (about 3") conical filter. It was collapsed. I drew a good vacuum 28” and added r134 after the first 12 once can the compressor started to cycle more normally about the end of the second can the compressor stopped cycling. The pressure never dropped below 45PSI on the low pressure side. High pressure was about 200 normal per the spec book for 85 degree day. I managed to add another can but could not get the compressor to cycle. I stopped when the evaporator iced up.
The spec book said for a continuous running compressor that possibly the fixed orifice tube was missing. ?? Is that what I removed. When I go to the auto parts store and ask for a fixed orifice tube they sell me a blue and white tube that fits in the evaporator inlet line. I replaced this tube the first time around. Two different parts stores have no record of the part I removed. Can anyone help? Do I put it back in and try again or do I leave it out