I tackled this job early last summer and although not mentally taxing, it is a long job, and you must take care to keep everything clean.

My original system had developed a slow leak, which required that I add one or two cans or R-12 every other summer.

I had bought 3 cases (12 cans each) of R-12 (At $12 a case) back in college, when I heard that the gov't was going to implement a $4 per can tax on R-12. I had exhausted my supply on my various cars, so it was time to make a judgment call.

The factory system was never great (It doesn't get as hot in Sweden as it gets in Texas!), and when the temperature got over 98 or so, it was just cool and not cold. I made sure that I pressure washed the a/c condenser on the front of the car every few months just to make sure that there was good air flow, and in addition, about 15 years ago, I added an electric pusher fan to the front of the a/c condenser.

I usually stay with original Volvo parts, however, for this job, I decided to go with parts from FCP Groton.

I ordered an expansion valve, a receiver drier and the o-ring kit.

The Volvo dealership recommends replacing the expansion valve whenever working on the system.

You must replace the drier when the system is opened. When you replace it, be sure you do it quickly, so that the drier doesn't soak up too much moisture. Also, the FCP unit does have a sight glass, just scrape off the black paint...

As far as the o-ring kit, it's up to over $32 now, and considering you only use 10 or so of the 0-rings, if I had to do it over again, and I had access to a really good source of o-rings, where I could by them individually, I would just label the old ones as I took them out of the a/c system and would then go to the parts store and buy them separately. Would save a lot of money, however, you can save time by buying the o-ring kit...

I took apart my entire system, and used Interdynamics Auto a/c Flush and Clean to remove all of the old oil. I bought this product at Pep Boys and still have half of the 32 oz container. I ran this through the condenser, hoses and compressor. I then poured some Castrol Ester Synthetic 134a Oil as a "Chaser", to clean out the Flush and Clean.

I used my compressed air nozzle to clear out the lines. I know you said that you don't have compressed air, however, you might want to invest in this, it really comes in handy.

I removed the compressor from my car and drained all of the old oil from the unit. I poured the Flush and Clean into it, drained it, then added the Ester Synthetic 134a Oil. I did this twice. I then soaked my new green 0-rings in the oil and then reattached the compressor hoses back into place.

I also took this time to replace the rubber mounting bushings for my a/c compressor. In addition, I also used a strap wrench to hold the compressor in place and then tightened the mounting bolts, so that the compressor belt was on tightly AND on nice and square.

As you are probably aware, it is extremely difficult to tighten the a/c belt and have it on there squarely.

I don't believe it is necessary to have the a/c condenser replaced. I just cleaned mine and it is still working great.

I replaced the receiver drier and the o-rings.

Finally, under the dash I replaced the expansion valve and the o-rings there also.

I bought Central Pneumatic's Air Vacuum Pump for $11 at Harbor Freight, and also a US General a/c Manifold Gauge Set for $39.

I used my compressor to draw down a vacuum and let it sit for 30 minutes.

I only took a few minutes to draw the vacuum and it held, so I charged the system.

I bought 12 cans of R134a at Sam's club for $28.

I added the correct amount of R134-a, I think it is the same amount of R-12, (I believe 40 ounces) less 10%, so about 36 ounces or so. (Maybe it's 48 ounces, less 10%, so 43 ounces, be sure to check your car for an a/c label that lists the amount of Freon in the system!!)

I was amazed at the results! The air was blowing out of my vents at 25 degrees!

It was never that cold with the R-12, usually 40-46 degrees on a good day, and when it was 100+ in Dallas, Texas, the best I could hope for was 60-70 degrees.

I have had to add one can of freon since last summer, and over the weekend, I replaced my a/c blower motor, which died on me a few months ago, and I looked in the sight glass on the drier, and saw bubbles, so I know that I will need to add another can of freon to bring it back to its peak performance.

I understand that it is not unusual to lose some of the 134a, as the molecules are smaller than the R134a.

I hope this information has helped you.
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If it needs to be maintained, repaired or replaced on a 1990 240, I've probably done it. '90 240DL, 287K looking forward to 300K badge (I'm Almost There!!!)(or sticker??). >>You haven't really worked on a car until you draw blood<< :-}