Changing out an AC compressor, questions.

[MeToo]

I'm in the process of changing the AC compressor on a 1976 Fleetwood, but a few things occurred to me that I'm not sure about as I haven't done this sort of job before and I'm an amateur who learns by experience.

1.Using the amount of oil drained from the old one to guide how much to put in the new one won't work here. The old compressor had no literally no oil in it, its been 3 days since the drain plug was removed and nothing. It seems it must have leaked out through the compressor seals. A while after it had seized, I noticed an unidentified liquid on the water pump, it definitely wasn't coolant or engine oil. Hmmm

 
2.I understand after changing the compressor, you then drive to a shop to get it vacummed, then R-134 is added which I'm told is blended with PAG oil anyway. If this is the case, then why put oil in the new compressor when its installed-especially if its going to get vacummed out and then replaced when the refrigerant is added anyway?


3. I thought I would also take the opportunity while the belt is off anyway to replace the belt since it hasn't been replaced in the time I owned it and there are small cracks in the grooves. However it is behind the alternator/waterpump belt so it seems I can't get it out unless I also remove the alternator/waterpump belt? Is there an easier way to get the compressor belt out for replacing?

4.I started draining the radiator as I thought it'd be easier to take the upper radiator hose off to help get the old compressor off. In the end I managed to get it out without having to remove the hose. I tightened the drain plug up as tight as I could, but if I squeeze either hose, coolant still squirts out the drain plug, whats up with that?
 
5.How do I get this black cap off the new compressor?

Thanks

[V63]

If your old compressor seized?  there is the concern of the system contamination. It sounds like the system was starved with oil, causing the latest failure?

There are some difficult choices ? do you go all OEM? with R12?  or not? THAT can get extremely costly, but also frustrating getting the quality OBSOLETE  parts required.

A major concern is the modern oils are NOT compatible with the original R12 mineral oil.

This discussion has been well covered and I might suggest reading some of the material already posted?

 Maybe do searches here of :
r12 , r134 , mineral oil, PAG,  VIR , a6 ,

[TJ Hopland]

The oil doesn't come out when the system is vacuumed out and the A6 is a different design than many other AC compressors so its got different oiling /pre oiling procedures that need to be followed.

Not sure what plug you are talking about, the one below the hose ports?  That's held in with that 'internal snap ring'.

On the belts yes to do the AC/PS belt you have to de-tension the alternator and remove the alterator belt.  De-tension the smog pump to remove the smog-water-crank belt.  Then de-tension the power steering pump that finally lets you remove the AC-crankp-PS belt.  Its just that easy.  Seems like a pain till you have to do a serp belt on a transverse engine where you have to remove the front wheel, inner fender, and engine mounts. 

I agree that the old compressor seizing there is a good chance it spit debris into the rest of the system that needs to be flushed out which also helps with the mixing oil issues which could also be what killed the last compressor.  The old R12 mineral oil when mixed with PAG turns into sludge. Depending on how long its been in there and how much air or other things its been exposed to how well the system will flush.  I have seen it where the solvent barely touches the sludge.  Its even worse if someone used a stop leak product then the system sat exposed to air. 

["Cadillac Kid" Greg Surfas 15364]

Ok, here we go again. When switching from R-12 with mineral oil to R-134a, the most critical factor is removing at least 95% of the mineral oil from the system. If not, R-134a combines with the residual mineral oil to form an unholy sludge that gums up anything in its path. To remove the Mineral oil correctly and successfully, the components must be flushed completely with an appropriate flushing chemical such as RX-11. This is best accomplished by removing the condenser flushing it separately, removing the TX valve and POA and flushing the evaporator and the removed parts. Then, as the parts are reinstalled with new o-rings the correct oil is added to the evaporator, condenser and (new) receiver/dryer in the quantities specified in the FSM.
Going back to the compressor. If the plug you are talking about is the one in the compressor sump ( the lower "belly of the compressor) if no oil comes out, it is empty. Typically 5-1/2ounces of oil should be added to the compressor making a total of something (check FSM to be sure) 10-1/2 ounces.
The compressor must be rotated several dozen times with the sump full of oil to prime the oil system, THEN the system should be pressurized and leak checked.
If leak free the system should be evacuated to remove all air and any residual moisture that may be entrained in the oil, and then charged.
Failure to follow this procedure seems to always result in a very short compressor life as does trying to use an A-6 compressor with a control system that cycles the compressor.
Greg Surfas

[MeToo]

Thanks all. I've run it on R134 for 13 years with no issues, so I don't think it will be gummed up with mineral oil as it was cleaned out then. I'm too young to have experienced R12 so I can't make my own comparison. My intention is to use R13 again, also because R12 isn't readily available where I am.

[MeToo]

Not sure what plug you are talking about, the one below the hose ports?  That's held in with that 'internal snap ring'.

Thats the one, is that meant to be the superheat switch? On the other side is short metal piece. Is it black piece on the outside to protect it in shipping and then I'm meant to turn it around with the shiny prong on the outside? Its just  that both appear to plug into the connector in the car so that confuses me.