Thinking of buying a new a/c compressor "kit"
 

First of all I am wondering where the dryer and expansion valve are located?
My car has had several compressors replaced in it's history. It is time to resurect the a/c again. I have been told that I need a compressor, expansion valve, and drier. This car has been converted to R-134a in the past. I am wondering if it makes since to convert back to R-12 or stay with R-134a?
I do not want to have to do this again. So I want to do it all right this time. But of course I need to do this in the most cost effective manor. Thank-you

The best value is to convert back to r 12.

Don't buy one of those kits off ebay. Mine lasted 20 minutes.

click the buy parts link, or call phil.

Buy a compressor, receiver/drier, O ring kit, expansion valve.

You can flush the system out with acetone and compressed air.

Replace O rings AFTER you flush.

I did not feel comfortable recharging my system, so I bought a couple of cans of r12 off ebay, and dropped it off at the dealer. It was 159.00.

Your 1985 SD should cool fine with R134 if it has the more efficient condensor. Count the number of tubes.

What's the point? If he is practically rebuilding the system, why not put r 12 back in?

;)

I'm new to ac work (except for what I've been overcharged for in the past), and I've never heard of mineral oil in the line. Can somebody explain the why's and wherefore's of using mineral oil? Also, why is acetone best for purging the system? Thanks

acetone is not best, it's just an available solvent.
best would be true R11 refrigerant, followed by 5 lbs of R12 blown through it. but that is illegal and very expensive.
they make refrigerant line flush solvents and sell kits at most parts stores.

Acetone dissolves oil, and is an excellent cleaner.

The real reason it is the best alternative is because it evaporates quickly.

It will leave your lines clean and dry

Thanks. What about the mineral oil?

Oil is there to lube the compressor. I am putting synthetic oil in mine today. I bought the flush used on dieselgiant and it's pretty messy.. I got two can's and it almost gone but I am not done yet. I have heard of using denatured alcohol to flush with too.

The mineral oil stays in the lines for compressor lubricant. I prefer 8 oz of frigie lube for my lubricant. It costs more than mineral, or ester. But still under $15

Convert back to r12 - lots of good info.

Check the dieselgiant site for good pics of where things are.

Call phil for a kit - just bought one yesterday, great deal!

There are three basic oils for auto AC use:

"Ester" oil which is the worst lub of them all but is compatable with both R12 and R134. Because of this many systems that were converted from R12 to R134 received ester oil.

"PAG" oil is a better lub than ester but, is NOT compatable with R12. Requires a very clean system during conversion.

"Mineral" oil is what was originally used in the system with R12. It has the best lubricating properties of the three but, is NOT compatable with R134.

Also, be sure to use the proper viscosity oil for the "R4" compressor.

Most failures are due from trash in the system (improper flush) or the wrong oil.

If you have the updated condensor on your SD I think you will be happy with R134. My "black" '85 SD wit R134 works very well here in the Texas summers. However, my W123 wagon is currently undergoing a switch back to R12 due to it's less efficient condensor.

What is in the kit?

I'm on my second summer with the ebay kit. I'm on 134 and it cools fine on the highway, its in the mid 90s here and the car can't really keep up in the city. If the compressor goes I'll get a kit from phil and find some r12 to see if its really better.