When the A/C stopped working in my '89 F150 (years before I bought the truck) the original owned never bothered finding out why and just left it. When I bought the truck, I pulled out the compressor and lines (don't really remember what my reasoning was) and got a non-A/C belt. A few years later, when I was rebuilding the truck after it got whacked (2018-2019) I decided to restore the A/C system and made the mistake of buying one of those cheap kits online that comes with a compressor, orifice tube, accumulator, and all of the o-rings. And now I have a loud bearing noise coming from the compressor when the clutch is engaged. (This started last fall)
I plan on doing a saginaw power steering conversion later this week, so I plan on replacing that compressor while I'm at it. I already had the refrigerant recovered last week, so I'm working with an empty system. But I still have the original A/C compressor sitting in my garage. The compressor spins smoothly, and the clutch spins freely independent of it, but it has been sitting open for several years now. So I am wondering if it would be a bad idea to just run some A/C flush or compressed air through it (or some other cleaning method) and use that, as opposed to buying a new one. Since the A/C system was completely empty when I first took the old compressor off, that would imply that there was a leak in the system, which caused it to stop working in the first place, so I would assume that it was still good when I first removed it, as long as it did not run with any contaminants in it.

 

You may find the insides of this thing to be much more complicated than you expected. For the money, just go buy one.

 

as picky as AC systems are about being clean I would not. If the compressor lets go you're gonna end up having to replace more stuff and flush everything out again, not worth it imho

 

Unknown = ri$k. If you do it right, your risk is MUCH lower. I'm still finding complete original pressurized R134a systems in JYs for substantially less than all the new (good) parts cost. I got this last week (including the hood latch support almost out-of-frame at the top) for <$200. It CAN be R&I'ed with the fender in-place. So that's my first recommendation - get the original R134a parts in good condition, and only buy new what you have to. In some cases, I've dropped the JY system in with NO new parts, and had it work for years.



But in my '93 F250 5.8L, I didn't have a good V8 system or parts, so I bought the compressor, manifold hoses, & dryer new.

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In any case, CLEAN everything - especially the parts that handle cabin air - before installation.

 

Well I decided not to risk it so I got a new compressor, which worked out because I would have had to drill/tap the compressor mounting holes on the E150 mounting bracket I had if I used my '89 compressor.