My 92 525 A/C is no longer putting out cold air after 12 years, never been recharged. Decided to do the conversion to R134a yesterday.

Followed all the instructions given on E34.net to the letter. Removed the compressor and drier to drain the oil from it, about two oz. came out of the compressor and a few drop came out of the drier, altogether not much drained out. I pour about 3 oz. of the poly ester oil from the rerofit kit into the compressor and 3 oz. into the new drier. (Bentley show the system capicity is 6.8 oz.). Replaced with new o-rings at all the connections and installed new R134a drier from BMA. Proceeded to evacated the system to -29 psi using a vacuum pump for a hour, closed all the valves on the gauge manifold and disconnected the vacuum pump, held it for about half a hour with no changes to the -29 psi vacuum. So I proceeded with the freon charge, placed the 1st can in and started the engine and A/C on, fan at high and temperture at lowest setting for the second can, but only half of the third can emptied into the system. At this point still no cold air from the vents and the system will not take anymore freon. The instruction said the system requires 4.5 cans.

Have anyone encountered this? Did I overlooked some steps? Any recommendation is greatly appreicated.

glen-sj