I need AC advice!

[Sparks]

I just bought a new compressor for my daughter's 86 300E from PartsShop(thanks Phil for everything)per my mechanics recommendation and after he installed it, the same problem is continuing.

He had converted the system to r134 due to a leak in the schrader valve and replaced the dryer and expansion valve. The system would blow cool but not cold and the high side pressure was fine but the low side pressure stayed too high and the needle jumped a little. He diagnosed the compressor as having bad reed valves, hence the replacement. This mechanic was a Mercedes dealers head tech for 12 years and has come highly recommended but he can't quite figure out what's wrong. He has checked the condensor and he says it flushes fine so he doesn't think that is the restriction.

Any thoughts? I don't want to keep replacing parts when their not the problem. Also, the compressor on the car was rebuilt in Dec 99 and is in great shape, if anyone needs one.

Thanks for any help,