Changed over to 134a with volvo kit last September but did not fill as there was a problem with the condensor & decided to wait till this spring. In the meantime I vacuum pumped out the air for about 30 minutes.Do I have to worry about any internal corrosion problems? What would indicate ?

If the system stayed evacuated then; 1) it passed an important test for integrity, 2) it will be in no worse condition than it was when you repaired it.

The question is...what was the reason for touching the A/C system in the first place?

Note: other than being open to atmosphere and dirt, the biggest cause of internal A/C component corrosion is the creation of hydrochloric acid when the hydrogen in water mixes with chlorine in R-12.

The reason the A/C was worked on was that I converted it using the Volvo kit to change from R12 to R134a. Of course prior to this I had the remaining R12 evacuated at a service facility so the chlorine in R12 is not an issue as far corrosion is concerned.Due to Issues with the old condensor which I will replace I put the system back together with new evaporator,dryer valve hoses & sealing rings & used a vacuum pump for 30-35 minutes to evacuate the air & remaining moisture out. The system is Sealed as long as there are no leaks.As long as I hear a "Whoosh !" when I disconnect the condensor it should be OK, right ?

Couldn't help thinking to fill in the bits you didn't actually write, but I suppose instead of a whoosh letting air and moisture in, you're going to connect a gauge to see how strongly the air would like to come in; then pump it down even more and longer before letting the R134a in. Oh, well, that is what I was thinking, as I have the same situation with one I converted, evacuated, but then lacked the R134a manifold (proper fittings) to fill immediately last fall. I'm worried my daughter will make me honor that "warranty" Rob speaks of;-)
--
Art Benstein near Baltimore

Any shop that works on this car will likely slap a dsclaimer statement on their repairs:
"Any system that is exposed to air or moisture for any significant length of time is liekly to experience multiple failures. We do not warrant the labor and materials associated with recharging older car A/C systems."

Or words to that effect. It's their catchall non-warranty statement. IT means any new parts are covered by warranty but not the actual work of recharging a second time, or the price of R134 refrigerant itself.

The chances of getting this system up and running without replacing nearly all of the major components, are small. Some of the new parts from the conversion kkit even may ned to be replaced again if moisture entered the system anywhere.

Not what anyone wants to hear but it's probably reality. Plan for pretty bad news, and be pleasantly surprised if you get out of there for just a $125 recharge and leak test.
--
Rob Bareiss, New London CT ::: '87 244DL/M47- 225K, 88 744GLE- 209K, 91 244 183K. Also responsible for the care and feeding of: 88 745GLE, 229K, 88 244GL, 146K, 87 244DL, 235K, 88 245DL, 236K

I have the original R12 system in my '86 240, and it stopped functioning several years ago. I was planning the following:
- flush system. Suggestions I've seen are to use paint thinner (compatible with ester oil), and to not flush the compressor
- replace all 0-rings
- replace receiver/drier
- vacuum pump, leave for a period, test that it held vacuum
- if not, test for and fix leaks
- re-vacuum
- add oil
- refill with one of the hydrocarbon based refigerants (eg. Duracool, Autocool)

Do you really think that this has little chance of working; that I'll need to replace "nearly all of the major components?

But being that I used a vacuum pump for 30 minutes & if all the seals are good & no moisture gets in & there is no air what would be the problem if the system is sealed ?