My 1985 300D is starting to leak 134A from the compressor manifold hose fitting at the bottom of the engine. I would like to "reverse convert" it back to freon during this repair. I do have freon based a/c experience and have all the tools except a vacuum pump. My question is what is the best way to get all of the ester oil out of the r4 compressor. Everything else can be replaced or THOROUGLY

oops, got button happy. anyway, thouroughly flushed. Can it just be drained or do I need to circulate flushing solvent through it while turning it by hand? Thanks for your input.Don't want to have system destroyed by traces of old incompatable oil.

If the compressor is orginal....

REPLACE it!!! Not sure on flushing it!


Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

If the compressor is in good shape there should be no problem reusing it. DO NOT use solvent to flush the compressor. Simply take it off, turn by hand and get as much oil out as possible, then fill with mineral oil and turn several times by hand to circulate then get as much out as you can. Mineral oil is not too expensive, so this is the most practical way to flush out the ester.

I have reverse converted with great success. You must flush the oil out thoroughly and then make sure that you get all the flush agent out thoroughly. Replace the filter drier, put in the mineral oil, evacuate and charge.

I have had trouble with the center bolt on the R4 manifold. I have actually had to retap the hole before. Assuming the bolt hole is in good shape and the bolt will thread straight in, put the manifold in place with new o-rings and tighten the manifold BEFORE tightening the strain relief brackets for the manifold and hoses. After doing this and getting everything else back together, thoroughly test for leaks before charging. If the manifold is out of place, the leak will be pretty bad, you could probably HEAR the leak.

Good luck,

Thank you for the info, the compressor, along with almost every other part (including the evaporator) was replace about a year before I bought the car. Of course they didn't replace the manifold hose assembly (the only thing they didn't replace). After looking at how much one is, I called a friend who works at a forklift shop and has access to hoses, fittings, and a crimping machine. He says he can recrimp a new hose on the manifold assembly for next to nothing. For now, I have added some 134a and a little ester oil so I can still have air (its hotter than Hell right now!!) and not harm the compressor running it on a low charge until I get the money, parts, and tools together to do this big job.