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Old 09-08-2004, 03:54 AM   #1
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Default Trying to replace ac compressor and clutch

Ok, I'm just a poor man trying to save some money. I have a 95 SE and the clutch and compressor locked up. I have managed to get the old one off and have captured the R134 (THANKS TO THE NEIGHBOR). Here'* my question. How much oil do I need to refill with the R134 and Where does it go, (HOW DO YOU GET IT IN WITH THE R134)? Also how much R134 is needed? Is there any further recommendations anyone can add for this job to be successful? Any and all Info would be greatly appreciated. Obviously this is my 1st attempt at ac replacement so please, don't laugh, unless you feel the need! I am selling this car so I don't want to be too loose with the wallet but I also don't want anyone buying this car and getting ripped off because of a lousy job! Thank *
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Old 09-08-2004, 10:34 AM   #2
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How long has the system been open to the atmosphere? Do you have access to a good vacuum pump? Was the system leaking before the compressor seized?

Unless you have your own vacuum pump, you will need to buy and install a new accumulator/dryer, and have the system pumped down. If you change the accumulator, you can add (unpressurized) oil to the new accumulator, then pump the system down and add refrigerant. The amount of oil depends on how much was lost from the system. You are supposed to drain and measure how much oil remains in the compressor you took off. I have my own pump, so I don't usually change out the accumulator. I have had good luck adding about 6 oz of oil under these circumstances. But, I suppose it is possible to run into problems by adding too much oil. The oil I normally add comes from Wal-Mart in a can with a couple oz of refrigerant that serves as propellant. There should be a sticker under the hood that tells you how much refrigerant the system takes when it is completely empty. You evacuate the system, (length of time depends on whether or not you have a new dryer - 30 minutes with a new dryer; two or three hours without) connect the can to the suction port, turn the can upside down and open the valve. The oil is pushed in by the two ounces of 134A that are in the can with the oil. You then charge the rest of the system in the normal way.

If you have your own vacuum pump, and the system has not been open to the atmosphere for too many hours, you can remove the moisture from the dessicant in the accumulator by pumping the system under a high vacuum for several hours.
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Old 09-08-2004, 10:51 AM   #3
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well i've been looking into fixing my ac system on my '87 for a month or so (to no avail but mainly because i'm too lazy to try it... ) but after lots of looking into it here'* what i know:

First you wanna see if you can find out why your compressor locked up. If it locked up due to just age, etc that'* for the best, but if it locked up because of deterriorated teflon rings in the compressor (this is referred to as Black Death in the car a/c world) then you'll have to look into how much damage that caused.
With deterriorated teflon rings, chunks of the rings (usually seen as lots of BLACK gunk in your lines, condenser etc) are broken out of the compressor and into the system. This usually clogs the system and causes compressor failiure (the clog in the system keeps the compressor from getting refrigerant/oil (the oil travels with the refrigerant) and thus the compressor fails.
If your system suffered this Black Death, you may have a good amount of work ahead of you (replace your lines to and from compressor, check condenser to see if it is cleaned out via flushing or if not, replace it, same goes for evaporator but less likely that the black gunk would have made it so far in the system).

Assuming that'* not the case here'* what you should do
Remove your old compressor, remove old accumulator (might as well get a new one of these to ensure your new system is in top shape, its only about 60-80 bucks new from a parts store). NOTE: the amount of refrigerant your system needs is usually listed on top of your accumulator on a yellow sticker, note this amount before getting rid of the old accumulator
--
At this point we're ready to begin oiling / final installation, do the following when you're ready to install the compressor / accumulator, and seal up your sytem as soon as you can (i.e. install everything and flush all in one fell swoop)

Using a flushing solution and shop air, flush the rest of the system (i.e. the evaporator and the condenser).
Similarly, flush out all the lines. (replace your old orifice tube too, its about $5 bucks).
NOTE the new components of your system, i.e. the compressor and accumulator are not to be flushed, (they're new and clean already!)
For the next step, make sure you have oiled up the O-Rings (any that you see and can find on the hoses) with some oil, if you can get your hands on new a/c o-rings, even better! Put the o-rings back in place once they have been oiled.
Now that everything'* been flushed, drop in the oil for the compressor into the compressor'* suction port. (I'm at the library here at Virginia Tech between classes so i dont have the exact amount of oil to put in, i BELIEVE it is 8 oz but don't quote me, i'll get you a better figure later tonight when i get to my appartment where i have a shop manual, in fact since my manual is for my '87 i recommend you get the amount of oil from someone else------------)
As soon as you put the oil in, mount all the lines on the compressor to make sure nothing else gets in.
Now move on to the accumulator, drop in the correct amount of oil for the accumulator (4 oz i believe SOMEONE ELSE CONFIRM THIS FIRST!!), and mount that immediately as well.

Now your system should be nice and closed and nothing should be getting in or out.

Next step is evacuating the system--
You will need a vacuum pump to evacuate the system. Vacuum the system down via the low pressure valve to (WILL GET YOU THIS FIGURE LATER TONIGHT). Once the system is vacuumed down to this pressure, disconnect the vacuum pump and let the system sit for ~45 minutes.
After 45 minutes, check the pressure of the system, it should not have changed from when you removed the vac. pump. If it has changed (I.e. pressure gone up), you have a leak somewhere (proceed to curse at that point!) Fix any leaks if your pressure doesn't stay down, iif you can't fix the leaks, i dont think i have to tell you that your system won't be blowin cold (or probably even running) for that long.

Next you have to turn the compressor a good 10+ times by hand. Be sure you turn not just the compressor pulley but the clutch itself. (it should be somewhat hard to turn it, the pulley on the other hand should turn with very little effort) There is a tool available to help you turn the compressor, i find that i can t urn my new compressor by hand so I don't need a tool but some people do need that tool (The tool is sorta like a Y shaped wrench that grabs on to the couple of screws on the compressor'* clutch so you can turn it easier, i believe it to be available for rent or purchase at many chain parts stores).


Now that your system has been flushed, components have oil, and has been evaccuated, all that'* left is to put in the refrigerant itself.

Find the low pressure valve on your system and give it the correct amount of refrigerant based off of the number you noted on the top of the accumulator earlier. DO NOT OVER OR UNDER FILL THE SYSTEM.
***QUESTION: DOES CAR HAVE TO BE ON WITH ENGINE RUNNING WHEN DOING THIS INITIAL CHARGE??? PLEASE RESPOND!!! I WILL CHECK SERVICE MANUAL TONIGHT AND GET BACK TO YOU***

Your a/c system should be up and running good as new now!

Notes:
I wouldn't use the captured R134a you got from the old system, might as well get new oil and refrigerant in there. What'* an extra 15 - 20 bucks for nice new refrigerant?

Regarding the Black Death thing, if your system had this going on, try your best to make sure there are no clogged passages in the condenser, sometimes flush solution comes out clean and one thinks he'* finished flushing but doesn't know there is an entire clogged passage of gunk! That'* why its a good idea to replace the condenser IF you have black death, if not then you're probably fine with just flushing.

If you don't have a vacuum pump but do have an air compressor, i have seen small boxes that convert that pressure into vacuum (i.e. turn your air compressor into a vacuum pump), I am not sure how well these work, in any event so long as whatever "vacuum pump" you're using can get the system down to the pressure it needs to be, you should be fine.

Don't skimp on small things like buying new o-rings if you can and lubing them up, and buying a good guage etc to read pressure... these things will obviously pay off in the long run.

I know it'* weird that you put oil in the system, then evacuate it! But that'* the process (the oil stays in there).

Use the right type of oil for your AC system, there are various available:
PAG, ester oil, (one more i think too).
ANYONE KNOW WHICH HE SHOULD USE? I'm assuming Ester OIl though! They sell these in small little cans (they are not pressurized).

Good Luck, I hope this helps,
Michael Diaz
ask any questions and we'll see if we can help.
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Old 09-08-2004, 10:53 AM   #4
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wow that was a heck of a post, sorry for length i guess? Anyways i knew they sold those oil in a can with a little refrigerant propellant but since my ol service manual didn't indicate it, i didn't mention it, anyone recommend one over another?

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Old 09-09-2004, 12:45 PM   #5
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For the DA-6 model compressor, add 8 fluid oz of oil into it.
The accumulator asks for 2 fluid oz of oil
Note: my service manual is for an 87 bonneville, i'd confirm before using these figures.

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Old 09-09-2004, 04:13 PM   #6
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seems like you could right a good techinfo article
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Old 09-09-2004, 07:03 PM   #7
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here'* the spec on the pressure for evacuation procedures:

System must be brought to 711.2 - 736.6 mmHg (28"-29"Hg) vacuum.
This is for sea level, for every 1,000ft (304.8m) above sea level, specification shoul dbe lowered by one inch vacuum (254 mm)

Factory service manual also notes that at 5,000 ft elevation above sea level, only 584.2 - 609.6mm Hg (23-24") vacuum is required.

Any problems reaching that vacuum level (assuming your vacuum pump is good enough to those levels) means you have to check for leaks.

Mike diaz

oh and about a tech info article: i think what i posted would be more than enough!! feel free to publish guys.
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