R4 Air conditioning compressor questions
I have a W123 chassis with dead air Conditioning. Based on reading many posts on this topic, I plan to keep the system R12.
As a first step I will replace the compressor. I pulled the old R4 compressor off last night and noticed that it had a "Notice" to the effect that mounting bolt holes were metric. So now I have a question--Are there different models of R4 compressor? I had hoped they were all alike and I could find as late a GM car that used the R4 and pull the compressor. Is that still a vialble plan, or are there different R4s. If there are different R4 compressors, which will work on my W123 (240D)?
One more question--How can I tell visually which is a good compressor--IS there a std failure mode ( like the front seal on the older A6 which left an oil streak on the bottom of the hood)?
What do I look for?
I will also get a new reciever/dryer, flush the lines, and apply vacuum for a long while.