A/C compressor leak

Hi everyone,
I'm looking for suggestions on what to do with what appears to be an A/C compressor leak on my 1976 911s. The compressor appears to be a mid-eighties unit which was upgraded by the previous owner. I have had the car for about 16 months and the air has worked great here in south Florida. However, ever since I bought the car, I have noticed an oily residue inside the engine lid just above the A/C compressor unit. Early this week, the unit stopped cooling any longer, although the blower is still blowing plenty of air. I also noticed that the accumulation of this oily substance inside the lid is much greater. My questions are:
1) Is this a problem with the compressor, and is this problem typical with these compressors?
2) Is this type of leak easily repairable without having to replace the entire compressor unit?
3) Can this type of work be done by any A/C shop or should I take the car to a Porsche specialist?
4) Approximatelly how much should I expect to pay to repair this problem?

Thanks

Ruben
1976 911s

WHERE is the oily residue coming from-specifically? If it is at the suction line or discharge line fittings, by the blue and red caps, you may just be able to tighten the fittings and recharge the system. Is it r12 or r134a?

Thanks for the reply

The dark oily residue appears to be comming from the space between the compressor housing and the compressor rotating unit. The residue leaves a long line impression on the lid like if it is being discharged in a fan-like fashion. I do not know what refrigerant is being used at this point. What is the relevance of the refrigerant? Thanks

Ruben

The relevance of the refrigerant is:1) r134a can deteriorate seals and hoses in a retrofit and cause them to leak and 2) The price of r12 is significantly higher.

My advice- sounds like compressor failure of the seals at the clutch assembly
Do yourself a favor and don't fuss around with this-buy a new compressor OEM and have a certified tech. pull a 30 inch vacuum to guarantee you don't have any other leaks-then drop in the r12 and be done. My guess to the price: compressor-$400.00
leak test- $75-$125
recharge r12- $100-$200
misc. $100.00

It gets worse. I just came back from the mechanic's shop and confirmed that in fact the compressor is leaking, small leak. However, when I lifted the lid and we started looking at the compressor, I noticed that the condenser apparently made contact with the top of the ignition coil and a leak is also present in the condenser (oily residue) It appears that when I changed the trunk lid several months ago, I left the condenser hanging too low and the contact finally damaged the condenser. Bottom line, total job including parts, labor, etc is approximatelly $1700.00. Anyone has any suggestions on how I can minimize the expenditures. Can I do any of the work myself and just leave the final R12 charging to the experts. Thanks

Yes you can do most of the work yourself and save money but you will lack the guarantee that it will work when you are done. Go to griffiths.com(sp)? and find a new or rebuilt compressor and a new condensor. buy them. install them-it is easy just look at it. when you are done-go to the mechanic and tell them to put a holding charge of nitrogen or whatever they see fit in the system-go home-wait a week-go back-if it holds the charge tell them to evacuate and recharge with r12-you should be good to go for less than $1000.00-good luck