Hey guys, quick question. Does any one know what a "ballpark" price is to have a 75 AC repaired/replaced.

I got a phone "guesstimate" of about $600 or less for all new parts. Now he didn't say which parts and I realize I need this in writing before I continue, but was just curious if anyone else has had this done and what you may have paid for it.

This guys says he "cut his teeth" on these. They have been around for a long time. Matter of fact I had my Park Avenue fixed by them several years ago. Did fine work but cost me more than they quoted due to supposed un-availability of reman parts as quoted but i digress.

Does this sound about right or is it way off?

How can they tell you how much it is going to cost without knowing what it needs? It may just need a charge. Start by shorting the compressor to see if it still works. Next, stop by a parts place and pick up one of the refill kits that come with gauges. Buy one that is an R12 replacement that has the oil in it already and has sealer (on our old cars, the seals shrink and allow the refrigerant to leak out). Follow the directions, and fill up your system to see if you can get it to work. If you are lucky, you will have working AC for about a tenth of the cost of their "guestimate".

If you want to do a conversion, you can do everything yourself. The final step of pulling a vaccuum on the system and filling is the only thing you need a shop for, and that will only be about 50 bucks. You don't need to change everything for a 134 conversion, either (don't believe everything you read). You have to flush the mineral oil out, change the accumulator, add PAG oil, and fill with a slightly different amount of 134. It won't cool as well as R12, though.

I converted my 92 Roadmaster to 134, and my 81 is still R12. I'll keep it as is and use an R12 substitute when the time comes.

A VOV will go a long way toward making a 134a conversion cool well.

http://www.imcool.com/articles/aircondition/VOV1.php

Napa sells them. They actually make two - one for normal climates and one for 105+ like a desert climate.

Yes, I'm going to put one in my 92 when I do a new compressor this summer.

Thanks for all of the GREAT information. I am going to try filling what i have. How do you short the compressor to make it run. I thought there was a low pressure switch that would prevent this. Not ever having worked on an AC system in don't know the ins and outs, only the basics.

BTW the VOV article was very informative.

Also, if i have to replace the system, how do i flush the system?

Thanks for all of the GREAT information. I am going to try filling what i have. How do you short the compressor to make it run. I thought there was a low pressure switch that would prevent this. Not ever having worked on an AC system in don't know the ins and outs, only the basics.

That's what you do when you short it, you bypass the low pressure switch. It is a standard method to check for compressor function. You can find the connector on the back of the compressor.

To flush it, you can use brake cleaner and compressed air. If you are going to open it up to flush it, make sure you replace the orifice tube.

And the receiver/dryer.

And the receiver/dryer.

Yes, I called it an accumulator above...

So do you guys have a preference on a parts supplier or manufacturer of parts for this?

Your local parts place will be able to get you lots of stuff. GM parts are common to lots of cars. To see what is available from regular parts places, check rockauto.com. You should have no problem with rebuilt compressors, recveiver/dryer/accumulator, condenser, orifice valves, seals, oil, etc.

Classic Auto Air (http://www.classicautoair.com/vintage_air.asp) can help with things if you need to go the restoration route.

If you need hoses, you can probably get them done locally from a shop if you are in a decent sized city.

Just for example, here are all the parts listed for a 1975 Deville at rockauto (you didn't say what model you have):
Heat & Air Conditioning
A/C Compressor

A/C Compressor Clutch Bearing

A/C Compressor Head

A/C Compressor Thrust Bearing

A/C Condenser

A/C Evaporator Core

A/C Expansion Valve

A/C Expansion Valve Screen

A/C Line O-Ring

A/C Receiver Drier

A/C System Valve Core and Cap Kit

Blower Motor

Heater & AC Controls

Heater Case Drain Hose

Heater Control Valve

Heater Core

Heater Hose

Inline Filter

Schrader Valve

Valve

I was looking at Rock Auto and all of the terms you listed aren't listed on their site. Do these parts have multiple names. I know the compressor and the Dryer and condenser. But the different valves I am not sure about. Especially when you start talking TXV, FOV or VOV. I saw an expansion valve but that was it.

NAPA should be able to supply you with the VOV.

Is that the same as the expansion valve?

I guess alot of questions would be answered if I had a picture to look at. Does anyone have an exploded view of basic AC system that would closely resemble mine?

Don't forget: before you go buying anything, just test your compessor, and get some refrigerant in it to see if you can work with what you have! If you can't do that yourself, just stop by a local garage and ask them to test it and fill it.

Is that the same as the expansion valve?

I guess alot of questions would be answered if I had a picture to look at. Does anyone have an exploded view of basic AC system that would closely resemble mine?

Yes it is the same. On my 93 Caprice, it went in the line that comes out of the condensor.

You're right. I need to check what i have first. You guys have been a great help. If someone does have a pic please post it for the next person at my level of ignorance. :)

A 75 Caddy uses a system known as "Valves in Receiver" (V.I.R.). The Exp. valve and Poa. valve in module form are mounted inside the top of the Receiver Drier near the evap. housing. This whole unit may be still available rebuilt as an assembly. But.....A/C systems are unforgiving and therefore proper and complete diagnosis is half the battle. Unless you know what you are doing, it may be less costly in the long run to have a V.I.R. experienced a/c tech look at it.
WMD

So is that the same valve as the FOV or VOV? If so does that mean i am stuck with that type of valve, and if so is 134a going perform any better or worse that with the FOV?

Looks like you're stuck, unless I misunderstand.

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=TEM&PartNumber=207337&Description=A%2fC+Expansion+Valve

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=TEM&PartNumber=208517&Description=A%2fC+Valve+In+Receiver+(VIR)+Assy+-+Remfd

The first link says something about TXV, which is interesting. That's different than a FOT and the VOV is a replacement for the FOT that obtains or exceeds the performance of a TXV without the reliability hassles.

So if that is so, would you guys recommend sticking with r12?

If you can get it, and you can afford it, ALWAYS stick with R12!

+1 for what Kevin says. R12 if you can find it. I would go with an R12 replacement before 134a.

BTW, you guys never really told me how to short it to charge it up. I know where the power connector is. Is that where you short it, and if so what do you short it to? The hot side of the battery, ground, what?

Nah, just connect the two terminals with a paper clip or similar.

Ah. So just short the two terminals together on the connector while plugged into the compressor?

Back to this again. I can't find R-12 anywhere. I just realized it is illegal to purchase it unless you have been certified by the EPA. So how do you get it?

UPDATE
Well i went and had it checked out to see if we could use the Freeze 12 and keep going. Turns out all of the refrigerant he put in it to test blew right out the back of the compressor.

He suggested replacing the compressor of course, and also the VIR with a different valve and a "cycling" switch. Apparently back then, compressors didn't cycle like they do now. Anyway, for the whole 9-yards it was $809. DAMN! I can surely replace a compressor myself, and any other part for that matter, but i am now unsure of, whether i should take his route or go back with the original style parts.

The refrgerant may have blown out the rear of the compressor from the High Pressure relief valve. If the system pressure is extreme that valve is designed to release excessive pressure. The pressure could be too high because of too much refrigerant, restriction in the system, poor air flow through the condenser etc. Did your mechanic use gauges to check the pressures?
WMD

Any news on this problem yet ??
WMD

The refrgerant may have blown out the rear of the compressor from the High Pressure relief valve. If the system pressure is extreme that valve is designed to release excessive pressure. The pressure could be too high because of too much refrigerant, restriction in the system, poor air flow through the condenser etc. Did your mechanic use gauges to check the pressures?
WMD

Yes he did use guages. It appeared that it was coming out around the backside where the compressor is put together (maybe a seal or gasket). As far as the air flow thru the condesor, he did tell me that the fan clutch needed to be replaced. But the refrigerant was coming out as fast as he could put it in. He suggested a faulty compressor and with 33 years of rode hard and put up wet, I suspect that is in fact the problem. I am, at some point, going to take the compressor off and see what I might be able to do with it. Maybe a rebuild of the compressor. Something I have been wanting to tackle for a while. If i get it open and discover that it is more than I am willing to tackle then i will go buy a new one.

So that is where it stands right now. Still riding with the windows down and sweatin like a pig. My car doesn't have leather, but the material used was a polyester of some sort and it makes me sweat as much as leather does.