A/c compressor

perhaps I exaggerated when I said pump down for hours but as noted, the vacuum is never too good and 30"Hg. is adequate. If you can attain more, so much the better.

If the receiver dryer is one combined unit, It does no harm to leave it in place and simply add a generic filter/dryer.

Please note filter/dryer! The original system may only have had a dryer and (I believe) some OEM stuff does not have an original dryer most do not have a filter. It is not required to change the receiver whether it is combined with the dryer or not. It is all right to leave the old dryer in place but cut it out if it is easily done. Used it has saturated silica gel, new the gel is anhydrous. but an old dryer creates very little resistance to flow. nothing important,but there is a tiny value in removing it.

After replacing the compressor, which is almost always the case, always add a filter. A new filter. The failing of failed compressor creates a lot of crud that you do not need fouling the replacement. I have seen sticklers who after a week or so will remove and reinstall another filter dryer pump down and recharge. This may be a "belt and suspenders" approach, but those who did it had plenty of automotive cooling experience.

Email direct if I can add to this.

Malcolm

It does not hurt to replace an orifice or a capillary metering tube but if the type of connections permit it , cleaning either up is acceptable.

Malcolm

Technically 30 in/Hg is a perfect vacuum, but in reality an ordinary vacuum guage is not nearly precise enough to measure the last remaining bits, but in this case it's not critical anyway.

That's not nessesarily true, the saturated silica gel expands and the pouch that holds it can burst. It happens and when it does it's a BIG mess and will normally destroy the compressor. I don't know what the 9-3 uses but usually the filter/dryer is easily accessible for replacement.

That's probably a little excessive, though a really bad failure may make it worthwhile. Normally this is only an issue in central A/C or heat pump systems where a compressor burnout results in lots of nasty acidic gunk in the hermetic system from the varnish burning off the motor windings. It's not particularly easy to flush out one of these systems so they make special cleanup filters to be installed after such an incident.

What I will standby is :

Clean up cap tube or orifice if present. Alternatively replace the thermal expansion valve if that is the metering device not a tube or orifice. I am leery of cleaning up TX valves.

Remove old dryer and filter and replace.

Retain receiver but be sure it is clean.

Pump down as far as possible. Replace charge and use gauges or very accurate weighing method.

Repeat with new dryer and recharge if you are a stickler. I feel it is cheap insurance.

Refrigerant, high pressure and moisture can produce nasty products even in an "open drive" compressor

After replacing the compressor, which is almost always the case, always add a filter. A new filter. The failing of failed compressor creates a lot of crud that you do not need fouling the replacement. I have seen sticklers who after a week or so will remove and reinstall another filter dryer pump down and recharge. This may be a "belt and suspenders" approach, but those who did it had plenty of automotive cooling experience.

Malcolm

My clutch pulley bearings failled (it seems). I think I only need a new clutch assembly. However, nobody sell it separate, so I gota buy the whole compressor.

I can replace the clutch myself with minimal tools, but people are recomending that I replace the entire compressor, which means I need to disconnect/reconnect a whole lot more?

Do I need to recharge the system? Replace the dryer/receiver? Since I believe only the pulley failed, theres no metal chips in there right? How can I check?

If the clutch is removeable then surely somebody sells it? Maybe you could find a new bearing, places like McMaster Carr sell that sort of thing. If you replace the compressor then yes you need to replace the dryer, O-rings at any fittings you disconnect, then pump it down and recharge it. There's probably no excessive metal shavings in there but I would still replace the orifice tube any time the system was opened.