A/C evacuation??

[fred2ka4]

Before I moved to NM my ac compressor had failed but since it was winter I didn't care about it. Now it's summer and I need A/C. I put my new/used but working a/c compressor on and installed the new belt, but now I have a question.

Someone told me that since I disconnected the a/c lines from the compressor unit, that I will have to have my system evacuated before I can have it charged. I am not sure and have never heard of this but I am not that familuar with a/c systems either, so I thought I would ask if anyone else has had to do this or is it ok to just recharge the system.

Any help would be appreciated and thanks in advance.

[fred2ka4]

No one has ever had to change out their A/C compressor?

[AudiRacerS4]

yes you have to use an evacuator before you recharge the system with r-134

[fred2ka4]

yes you have to use an evacuator before you recharge the system with r-134

Thank you, that's all I needed to know.

[WunderWagen]

Since you also disconnected the AC lines this means air and moisture got in there and probably ruined the receiver/dryer. Anytime your AC system is opened up for an extended period (hours not days) then the receiver/dryer has to be replaced. FYI

David

[arorem]

if you didnt replace the o-rings, than it would probly be smart to check it for leaks by seeing if it will hold a vacuum.

[fred2ka4]

Since you also disconnected the AC lines this means air and moisture got in there and probably ruined the receiver/dryer. Anytime your AC system is opened up for an extended period (hours not days) then the receiver/dryer has to be replaced. FYI

David

Where is the receiver/dryer located?

[Toyotatech]

30 min. with the lines disconnected is enough to ruin the desiccant in a receiver dryer and should be replaced, failure of the receiver dryer will cause more ac problems due to it's inability to remove moisture from the system.

[fred2ka4]

30 min. with the lines disconnected is enough to ruin the desiccant in a receiver dryer and should be replaced, failure of the receiver dryer will cause more ac problems due to it's inability to remove moisture from the system.

OK, where is the receiver dryer?

EDIT:

OK, I found the receiver dryer but is this something that needs to be purchased new or can it be used?

[Toyotatech]

It needs to be new. Running a vaccume in the system during the evacuation won't remove moisture from it. A new one from audi is around a $100. You will still need an evac after installing though. The only way a used one would work is if you knew it was in a car with a good working ac system and it was removed and reinstalled very quickly. The cheapest route is to just by a new one right away to save yourself the multiple recharge fee's.

[fred2ka4]

I found some used AC dryers on ebay but what is the difference between air/moisture getting in through the exposed ac lines and removing an ac dryer from a car. When you remove the ac dryer won't it go bad as well because of the air and moisture?

EDIT:

Question answered with above post ....... I type to slow .......

[Toyotatech]

Yes, unless it is some how put in a vaccume as soon as it is removed and plugs installed on the openings.

[Toyotatech]

You could try not installing one if you don't want to spend the money, if there is too much moisture it won't ruin parts (unless there is metal shavings from the old bad compressor in the system, there is a filter in it that removes contaminates) it will cause pressure problems and inadequate cooling.

[fred2ka4]

You could try not installing one if you don't want to spend the money, if there is too much moisture it won't ruin parts (unless there is metal shavings from the old bad compressor in the system, there is a filter in it that removes contaminates) it will cause pressure problems and inadequate cooling.

When I disconnected the ac lines to replace the compressor the lines just sat on the ground for about 7-8 days, so there goes my 30 minute window ........

About a week or two before the ac went out it wasn't cooling like it used to but that could have been a sign of the compressor going bad. If it's not to expensive to have a system evacuated and charged then I will try that first to see if it works. If it costs a good amount then I'll wait as I don't want to waste money.

[djwimbo]

If your compressor took a crap, the likelihood of metal shavings being in the system are greater than optimal.

I'm unsure of what type of expansion device you have. IIRC it's an orifice tube, early B5's used them. If you do have an orifice tube, you should replace that as well. Normally they go for ~$8 and 99% of the time they're universal. The reason you should replace it is b/c the metal shavings will get caught in it, and either reduce it's effectiveness or clog it all together.

Any time you open the system, you're supposed to replace the receiver drier. I've gotten away w/ it quite a few times with it being open for 30-45mins. If the system was open for more than an hour, I wouldn't question replacing the receiver drier. The A/C will not function properly if the system is "wet". This is the idea behind putting the system in a vacuum. The vacuum lowers the boiling point of the moisture in the system. Thus causing it to boil, and be removed from the "sealed system". Text book says a minimum of 30min vacuum, and the system should be able to hold 28in.Hg of vacuum w/o any leaks.

My advice is to have the new receiver drier installed immediately before the Evac and Recharge. If you don't have access to the tools to do the Evac & recharge, I suggest having a "professional" do it. It'll cost anywhere from $45-80 for the Evac & recharge (plus the cost of refrigerant-R134a) and whatever labor would be to replace the receiver drier. Probably only .5hr on top of the Evac/recharge cost.

A/C stuff is expensive, I'd hook you up on a deal, but you're a few too many miles away

[fred2ka4]

I have the new/used but working ac compressor installed with the new belt and everything so I guess I'll just have to wait a little while longer until I get a new dryer and do it right the first time.

As it is I have a little problem with my cam tensioner seal that requires my attention first. It's not that big of a problem as it's just leaking a little oil but since the car is down anyways neither is a rush.

[fred2ka4]

A new one from audi is around a $100.

I found this if anyone else is interested and it is a genuine Audi replacement part.

http://www.purems.com/products/product.php/II=1116