no way to repair yourself be very careful going to wrecking yard may cause more problems with compressor dirty you can flush and replace parts yourself to save money then have shop evacuate and charge system. system must be taken apart drier orifice and compressor removed flushed with an appoved flush solvent like dura-141B or an in-line filter installed (easier to flush.) then install new or reman compressor will have to add oil for either r134a or r12 use all new o-rings coated with refrigerant oilif changing to R134A you will have to install new fittings
note I am a mechanic have specilized in A/C for 18 years if you need help let me know by posting be glad to help
i agree with hiboy,I bought mine at a bone yard and walked around looking for stickers under the hood with a recent service date,not that it means much but atleast it was worked on recently.