Tails

Rob,
If you are a competent DIYer you an dissemble the compressor and check the internals, however, if you have gas in the system it should be captured by a licenced person. If the gas has leaked out you can remove the compressor and check for the name and model of the compressor.
If you then do a search on the web, you should be able to located a manual together with the spare part drawing like in PET for your compressor.
Strip down the compressor, check the internals and renew parts as required from the manufacture or agents, thoroughly clean all parts and re-assemble compressor with new gaskets, "O" rings etc.
Recharge the oil suitable for the refrigerant in use.
WYAIT, renew all "O" rings, check the expansion valve, check the high pressure switch, check the freeze switch, check the clutch for slippage and operation via a 12 volt supply, check all electrical wiring for continunity, clean the heat exchanger by removing the vent fan to gain access and using a tooth brush and cleaning solvent clean the exposed fins on the evaporator you can see.
Renew the liquid receiver and dryer.

Button up the system and take it to a auto refrig technician and have him evacuate the system with vacuum pump and recharged correctly.

If you have a rear cooling system undertake similar work on the evaporator and fan etc., before evacuating and recharging the system.

frankle951

I would replace the expansion valve !!!!!!

Adamant1971

I have an expansion valve new in box you can have at my cost. I will need one but can order another from Roger.

Bilal928S4

I got a new compressor from amazon for a little over $300.

Alan

yes - this discussion is about a 928 and this is true of all model years.

Many folks seem very confused about this - whilst this may not be true of absolutley all cars - it is also true of the vast majority of cars ever made with AC. It is this way for simplicity and cost reduction, it saves having to have 2 completely different temperature control methods.

It is of course quite a bit less efficient this way...

Alan

928 at last

I'm in for a toasty run....no time to deal with it now.
P.S. I would only deal with Frank under duress, and it would have to be extreme. His prices are outrageous, and I'm being generous here....
I'll go with Mark Anderson first and foremost.

928 at last

Thanks Adam.
I already have some parts for the pre-planned re&re. One new expansion valve in already, and the other in the box, so I'm good there, but appreciate the offer!

928 at last

Thanks Mike. It's been changed out once at least though, and I don't know if any PO got creative with the mounting. So, if at all possible, I'd prefer to replicate what's in there now.

928 at last

Prefer to think of myself as an "Incompetent DIYer".
Electricals check out...freeze switch was bypassed due to malfunction, so it's up for renewal. Evaps and condenser already thoroughly cleaned. "O" Rings and expansion valve already done for the rear system.......
Never been inside an AC compressor yet though.....looks like I may be going where others have boldly gone before ......I'll likely rebuild as a spare though...no time with summer essentially here now.

928 at last

Thanks for the lead!

Adamant1971

True, but I have found that in person he is way more reasonable than by phone or email. Defiantly mark over frank.

928 at last

Another myth dealt with....Thanks Alan. I was operating under the assumption that this was normal.

GregBBRD

"High" and "low" pressures, in the A/C system depend on two things. The compressor needs to be able to suck low pressure gas and turn it into high pressure gas. The expansion valve/valves need to be able to convert high pressure liguid into low pressure gas (this is what actually makes the "cold" that comes out of the ducts.)

If the compressor or the expansion valve/valves are bad.....you will not be able to make "presssure".

The compressor has pistons....or vanes....that do the actual "compressing". There are "check valves" that keep the gases from going backwards. (An A/C compressor is very close, in function, to a 2 stoke engine.) Damage to these check valves will allow gasses to "flow" both directions and not allow pressure to be made.

The expansion valve controls the amount of liquid that can "spray" into the lower pressure "gas" side". If it breaks, uncontoled amount of liguid will flash to a gas....releasing any pressure that the compressor might have just made.

Used compressors are a bad investment. Also tough to get a decent rebuilt one...same problem as most "rebuilt" things.....the less the "flat price rebuilder" spends on rebuilding something, the more profit they make. I completely "gave up" on rebuilt compressors....or at least will not warranty anything that goes wrong with the compressor, if the customer insists of me gettting one. (The last 10 I used, before giving up....all leaked out fo the front seal or from some other place on the compressor.)

Do yourself a favor. Buy a brand new Denso compressor. I sell them for $425.00....if you hunt around you can certainly find one cheaper, in these "wonderful" days of the Internet. They come complete with a brand new clutch.....ready to install. Really great value!

Buy a new dryer and a new expansion valve. Clean the front condensor (especially between the condensor and the radiator. Clean the front evaporator (you may want to remove the fan assembly, if it is really plugged up, but you can look through the connector boot to see how badly it is clogged.)

If you have a rear A/C.....check it carefully for leaks.....common for the expansion valve, back there, to leak, too.

worf928

+1.

$425 from Greg is a good deal.

I, just a few weeks ago, found $400-ish new ND compressors in several places.

And from now on, with any 928 with a high-mileage compressor that's what's going on the car if there are any signs of leaks (and there will be.)

I haven't tried a 'new' $400-ish compressor yet. I sure hope they're not too good to be true.

danglerb

Cost of parts to end users I think kills any value in DIY compressor repair, clutches can be crazy expensive.