Hello,
I've had two AC compressors seize up on me. After some posts here and elsewhere it is clear that the reason the second one seized up is probably because of stuff in the system that I didn't get flushed out.

Now, I'd like to get the job done right. What needs to be replaced and what is the flushing procedure (I'll probably pay someone to do that...). Compressor, orifice tube, and accumulator need replaced? The rest can just be flushed?

A shop quoted me $1400 for the job which seems absurd as I've done this work before and labor can't be more then 4 hrs.

Thanks a lot!

DO NOT monkey around . Get some real AC flush that you know will blow out completely, most parts stores will carry it, or get this stuff http://www.nostalgicairparts.com/ac/tools-and-more-14.php
( one of those flush guns is nice, but a cheap $3 siphon gun from Harbor freight works great for getting the flush into the system, and a rubber tipped blow gun for blowing it out. you need to have a GOOD air drier on your air line)
A qt of that should do the trick, remove the condensor, and do it flat, easier to blow out the debris than blowing it uphill
Clean all lines and fittings until all run clean. replace accumulator , Replace all orings, do not use the Ester oil on the orings, it will dry them out and they will leak, either get a can of old style r12 mineral oil for the orings, or get a bottle of Nylog http://www.acsource.com/index.asp?PageAction=VIEWPROD&ProdID=185&HS=1
Instead of putting a used compressor on , after all that work, which will probably have a leaking shaft seal
Might want to consider a new one , for less than the cost of a rebuilt. I buy and install lots of compressors that I get from http://www.nostalgicairparts.com/ac/compressors-41.php
These folks ( I just ordered another one this week that;s going in someones car ) I always put those Sanded style 709 double pulley jobs in for $185. The things work fabulous. Much less engine drag than a stock compressor and better cooling. you have to tilt the pipes a little to the sides on some models, ad on some you need to run a seperate ground wire, but they will fit and they cool great.

A variable orifice valve is a good idea if you live in a hot climate.
After flushing, you will need to run the vacuum pump overnight to get the moisture from the air lines out

Those suction line filters have pretty well fallen out of favour and most AC suppliers don't even carry them any more as too many people were just using them instead of flushing and the things would clog in short order and the restriction would quickly cause a compressor failure.
You can still get ones that will co onto a high pressure line between the compressor and the orfice either crimped in a rubber line or as a metal compression fitting for a tubing line at most mc parts stores.
I've never used one, I'd rather take the extra time to thoroughly flush the thing.
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-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '92 Ford F350 diesel dually

Great advice! Thanks everyone.

What about having a shop flush the system? Am I better off doing it on my own because I will be more meticulous or do they have special equipment? I will have access to a large air compressor and a full shop... everything but the experience!

I am planning on getting the ac compressor and accumulator off a parts car that I have (w/ a good, sealed system). Any problems w/ that?

I figure I will buy the orifice tube and o-rings.

What about oiling the compressor? If I use a used one, should I drain it and refill it w/ the quoted amount of oil for the entire system (I think I have a hayne's AC book w/ this information)?

Thanks again!

wow after two bad installs you are going to use another used unit?
very interesting.
good luck

You can add a small filter screen to the input side of the compressor (or in my case, to the output of the evaporator) to catch any debris in the system. I add one when my system is opened up. See the FAQ for details. Debris usually ends up in the compressor, ruining it, or at the orifice valve, plugging it. It can be VERY expensive.
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See the 700/900 FAQ at the "select shortcut" button, upper right of your screen.

See:

http://www.brickboard.com/FAQ/700-900/HeatingAirConditioning.htm#AirConditioningSystemMaintenance

The Compressor Guard screen is made by Airsept:

http://www.airsept.com/index.php?loadmod=compressor
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See the 700/900 FAQ at the "select shortcut" button, upper right of your screen.

Hey , The receiver drier ,and orfice tube need to be changed out . The system needs to be flushed individually ( all lines ). The evaporator can be flushed at the fire wall when you change out the orfice tube . It takes time to get the system clean . The hardest thing to clean is the condenser in front of the radiator . You can use brake cleaner ( not aresol can ) and air pressure until it is clean but make sure you have enough it takes quite a bit until it is clear . Finish up with regular ac system flush . Vaccum system down real good . Some people like to cheat on this . I would pull no less than thirty min. vaccum to boil out any moisture . Make sure you get quality seals also . The second compressor probably failed due to trash in the system . It is expensive to get the job done right . I would check out FCP GROTON for the parts . Most A/C shops will tell you the compressor cost around 400.00 + You can save yourself a bundle if you can do the job yourself (providing the job is done right). Hope this helps . larry

hello
i use non clorinated brake cleaner to flush system,
good luck
mike

Has anybody used envirosafe as an alternative to expensive R-12?

I'm interested in that $150 compressor option -- what modifications need to be done for it to hook up to a 940? Its not a major issue?

Here's an idea for cleaning the system out: I have access to an old condenser and lines, and even have an extra evaporator (but man is that PITA job!) -- I could just swap out the whole system and save myself some hassle. Is there a way to check old (used) components to see if they have any debris in them? Is it something you an just look at or blow some compressed air through to get a general idea?
Also, if I didn't want to swap out the evaporator, how good of a cleaning job can you really do on it while its in the firewall?

Running vaccum for much more then an hour seems to be overkill to me? I mean, with that much vacuum the liquids we are talking about (water) vaporize pretty much instantly. Organic chemistry taught me that. What's the consensus on that?

Thanks again!