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,