I have done 134 conversions at all different levels from a simple addition of oil, adapter fittings, evac and charge, all the way to changing hoses, condensors, flushing, filter drier, Ester or PAG, yada, yada, yada.

Regardless of the method, the statistics show that converted systems, regardless of how much work or parts were thrown at it, are on the average, short lived.

In the past I converted lots of R12 systems to 134. I have not seen very many of them last for the long term.

Steve Brotherton, who used to post here often, has done hundreds of conversions and kept detailed records on all of them. His conversions were professional and thorough, not simple adapters oil and charge. After time his data, which was much more scientifically kept and analyzed than mine showed the same thing. The average life of even an expensive 134 conversion was a couple of years.

Another member here went through a thorough conversion on a 123 car about four years ago with the determination to build a solid 134 system from scratch. To satisfy his own experimental nature he had a no limit budget with PF condensor, new compressor, hoses, and was even replacing the evaporator at the same time and did some careful work with the aux fan and its controls. After a year or so, he even gave up and reverse converted to R12.

As I said. I have done a number of conversions and some of them have worked out surprisingly well over the long term, but none of the successful ones have been on a German car. If someone today insisted that I convert a system in decent shape to 134 I would still do it as long as they are the sort that will pay their bill, but I would warn them beforehand that statistics are against them.

BTW, if it takes $90 for enough R12 to charge an MB, you are paying too much.