I have been given a factory new R4 for a GM car . I will be using it in 1983 Mercedes 300SD . It is my understand that the R4s for that Mercedes is configured differently -

Karl on usenet said - " A word of advice on buying a replacement compressor: Any one you get that does NOT come from Mercedes will have the front bearing cover installed UPSIDE DOWN. Look at the cover on the front behind the clutch. It will have 4 bolts. Between 2 of the bolts will be an embossed X. This is the position of the oil hole to lube the front bearing. The R4
compressor was originally designed for GM cars with the compressor mounted
on top of the engine. The X and the inlet/outlet port is UP. Mercedes used
the compressor but rotated it 180 degrees and mounted it under the engine.
This put the ports DOWN. Then they rotated the front cover so the X is UP.
Oil does NOT flow uphill. If you use an aftermarket compressor with the X
down, you will starve the front bearing of oil. It may last a week, a month,
6 months.... depends on the quality of the bearing they put in "

I want reconfigure this compressor so it will last . Can it be done somewhat easily . How do I get it apart to rotate the front plate 180 deg and back together not damginging anything. I really need some help . - Thanks