Where can I buy a/c fitting for 928 S4?
 

I want to recharge the a/c on my 1988 928 S4, but noticed that it has an unusual fitting where the refridgerant is added. Do any of you know where I can buy the adapter so that I can add refridgerant to the a/c system?

It should be a standard R12 fitting...if the car has been converter it will be an R-134 fitting. You should determine what you have first. The proper way to conver to 134A is to change the expansion valve, dryer and then flush it out and refill with 134 A and compatible oil. You can't mix the two gasses.

Any decent auto parts store can get you those fittings...but be careful, never attept to charge through the high side...all gas should go in on the low side and you should really vac it down first.