My 560sl a/c compressor has failed. I believe from the looks of things that it's simply the seals that have gone bad. Compressor is not seized and don't see any signs of metal particles in the discharge ports of the compressor. Compressor is caked-up with oil and attached dirt.

I'm replacing the compressor and am not sure where the oil is put in? Do you add it directly to the compressor or to the system during the charge-up with r-12?

Also, I'm considering flushing the system, but don't know where the expansion valve is located? Is it behind the glove compartment box?

Lastly, I'd like to install a suction side filter. Can that spliced by me or is it something that must be done at a shop?

Thanks!!