I am assuming you are referring to the shaft seal. I have replaced these before and if you have a sanden compressor then it will go better than normal but.............if you do not have good experience with working on compressors than I would highly recommend that you just order one. You will be money and time ahead. Most of all you will be much less frustrated.
Cusser
+1y
Absolutely agree !!! Everything MUST be kept PERFECTLY clean, and you'll still need a little luck. I'd suggest a rebuilt (Air Pro) or new from ackits.com. That's what I've used for the last decade on mine. Don't get a cheapie rebuilt one, you'll likely be sorry. And even if such is warranted, you'll waste the cost of your refrigerant and your time.