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Inside workings of compressor help

JerryHughes on Mon January 12, 2009 4:59 PM User is offlineView users profile

Year: 1997
Make: Saturn
Model: SL
Engine Size: 1.9 L
Refrigerant Type: R-134a
Ambient Temp: ?
Pressure Low: 35?
Pressure High: 50
Country of Origin: United States

Hello,

I have a rebuilt Ready Aire #2388 compressor (DKV14a compressor?) and hope someone here has a good, working knowledge of how it is assembled. Problem is, when installing the o-ring in the intake line side of the compressor I lost the o-ring inside the compressor. After taking the compressor end off and getting the o-ring back I may have assembled a component wrong. When trying to fill the compressor, the shop told me the high side reading was only about 50 p.s.i. and at the current temperature that day, it should have been three times that. I "think" the low side reading was around 35 p.s.i. but I'm not sure but I was told it was normal.

Remembering back to what went into the compressor, there was a large (maybe an inch in diameter by about an inch and a quarter long) brass cylinder that had a small brass pin centered at one end. The main end of the compressor, where this brass cylinder seated, had a small hole and I assumed the brass pin was supposed to seat in that hole. It did fit perfectly. For a look inside the compressor when I had it apart please go here. http://www.youtube.com/watch?v=MsexYNPwioc The area where the brass cylinder seats is the large, machined area toward the lower side of the compressor---note the centrally located hole where the small pin was "supposed" to seat.


After trying to pressurize the system and not getting the high side to full pressure I wonder if that large brass cylinder was supposed to be assembled with the small brass pin towards the other end or turned 180 degrees. I didn't notice any other parts falling out of the compressor unless there may be a possible o-ring I missed, that would also not allow the compressor to come to full pressure.

Would anyone in the know please take a look at the movie and see if the cylinder pin should have been assembled the other way or if there may have been an o-ring from that end that should seal somewhere? Thank you very much. For a look at the complete compressor, with "red arrows" pointing to the point where the compressor was disassembled, please go here------
http://www.autoacforum.com/messageview.cfm?catid=2&threadid=20176


Jerry

Chick on Mon January 12, 2009 8:38 PM User is offlineView users profile

If you put it back together just as you took it apart, it should work. You have a variable displacement compressor I believe, and although I never took the DKV14a apart, you may have a bad control valve, or it's undercharged. They need the full system charge to operate properly, and you didn't list the ambient temp, that could helps us help you.. I do know that the big brass plug is an adjustment and it's very sensitive, usually has a cover with a warning on it I believe, at least on factory compressors, not sure on remans..Thats about all I can offer..Get the ambient temp it was charged at, was a deep vacuum puulled?, system full amount charged back in?

-------------------------
Chick
Email: Chick

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Freedoms just another word for nothing left to lose

JerryHughes on Mon January 12, 2009 9:26 PM User is offlineView users profile

Hi Chick,

Thanks for getting with me on my problem. Yes, I should have taken better care when taking it apart. Could kick myself in the butt but too late for that. The ambient temperature was about 60 degrees. Yes, a deep vac for one hour was pulled. The tag under the hood stated that 1.5 pounds of R-134a was needed and that's what went in. It was fully charged but the output on the high end from the compressor wouldn't go over about 50 p.s.i. Is there some place I can get some drawings so I can at least see if the brass cylinder should be installed in the opposite direction? Thanks,

Jerry

TRB on Mon January 12, 2009 10:08 PM User is offlineView users profile

Might consider going to a wrecking yard and getting a cheap used compressor and break them down side by side.

http://www.ackits.com/diagrams/Nihon.pdf

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

JerryHughes on Mon January 12, 2009 11:14 PM User is offlineView users profile

Thanks, TRB, that is one option. I am going to check the price of pick and pull compressors soon. If not too expensive, I may end up doing that. But I wonder if junk yard compressors from another 97 would be the same as mine?

Jerry

Edited: Mon January 12, 2009 at 11:15 PM by JerryHughes

GM Tech on Tue January 13, 2009 9:13 AM User is offline

As I recall, that compressor is a rotary vane unit from Diesel Kiki-- and the last one I dealt with did not pump enough to suck in any charge--UNTIL I forced the full system charge in- Then it started pumping correctly. These can be a PITA. I believe I even overcharged it just to see if compressor would/could pump- then removed the overcharged amount, and compressor started pumping fine....

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

JerryHughes on Tue January 13, 2009 9:37 AM User is offlineView users profile

Thanks for that info, GM Tech. They had a really hard time getting all the fluid in, shaking the cans upside down to get all of it in but I don't know how long they waited to see if the compressor would start to run after that. After the second can was in, one of the techs got in the car, I assume to shut the compressor off. Do you know how long you have to wait until the compressor would start up after filling? But then----he said the compressor wouldn't go past 50 p.s.i. so I assume the compressor did start, just didn't get to full pressure.

Jerry

Edited: Tue January 13, 2009 at 9:38 AM by JerryHughes

Chick on Tue January 13, 2009 1:42 PM User is offlineView users profile

It's very possible that the compressor never engaged if it only got to 50psi and the outside temp was 60+.. Static pressure should've been higher.. But I agree with GM tech that the whole charge needs to be in there, it's odd to hear that a "tech" is using cans.. You are using R134a right? Bring it to a shop equipped to fill the proper charge by machine if necessary..

If you have a problem with the cvompressor, you can't bring it back once you opened it, so if needed, check out Ackits.com for a quality reman, also I see they show one with a thermal switch.. Make sure you have the right compressor, if it's different it may not be engaging the clutch..just a thought.. Hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

GM Tech on Tue January 13, 2009 2:00 PM User is offline

I don't use cans- the particular day in question was too cold-(at home) even with a machine to force all the charge in- so I was trying to suck some in- out of my machine- and it was not working-- the next best thing I did was let the machine pull an extended vacuum/recycle to warm the tank- then it would all go in at one shot....That is one of my biggest problems- a machine will spoil you- and sometimes you have to think like a DIY and remember they are using cans.....to help solve their problems..

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

JerryHughes on Tue January 13, 2009 6:52 PM User is offlineView users profile

Quote
Originally posted by: Chick
It's very possible that the compressor never engaged if it only got to 50psi and the outside temp was 60+.. Static pressure should've been higher.. But I agree with GM tech that the whole charge needs to be in there, it's odd to hear that a "tech" is using cans.. You are using R134a right? Bring it to a shop equipped to fill the proper charge by machine if necessary..
If you have a problem with the cvompressor, you can't bring it back once you opened it, so if needed, check out Ackits.com for a quality reman, also I see they show one with a thermal switch.. Make sure you have the right compressor, if it's different it may not be engaging the clutch..just a thought.. Hope this helps..

The shop was going to use their "reclaimed" R-134 and I decided I didn't want to use something that was recycled from a lot of other cars. For instance, if someone brought in a car that was filled with something besides R-134a, I wouldn't want to take a chance using that. So to be safe, I brought in two cans of new R-134a for the tech to put in. And I can't return this compressor because I had to take the end off to retrieve an o-ring from inside. When I opened the compressor, I voided the warranty. Thanks for your input.

Jerry

JerryHughes on Tue January 13, 2009 6:55 PM User is offlineView users profile

Quote
Originally posted by: GM Tech
I don't use cans- the particular day in question was too cold-(at home) even with a machine to force all the charge in- so I was trying to suck some in- out of my machine- and it was not working-- the next best thing I did was let the machine pull an extended vacuum/recycle to warm the tank- then it would all go in at one shot....That is one of my biggest problems- a machine will spoil you- and sometimes you have to think like a DIY and remember they are using cans.....to help solve their problems..

If 60 degrees may not have been warm enough for the compressor to engage, how would I know that? I can only take the tech's word, that something was wrong even if he didn't know what he was doing. Ugh. Thanks,

Jerry



Edited: Tue January 13, 2009 at 6:56 PM by JerryHughes

Chick on Tue January 13, 2009 7:06 PM User is offlineView users profile

That is why it doesn't hurt to get a second opinion and also ask questions. I realize you didn't know what questions to ask, but you're here now and we are getting more information.. If the compressor didn't start/engage then you might have an electrical problem, like a blown fuse, thermal switch problem if so equipped. If the shop "only" used their recycled refrigerant and didn't have a tank of virgin R134a on hand, run don't walk away from that shop. Before you give up on the compressor, bring it to a shop that specializes on AC repair and have it recharged correctly with virgin R134a, from a tank, with either a machine or scale and then ask questions if it doesn't work, like is the compressor engaging, is 12v getting to the coil, if not, were the fuses checked, relay etc.. After the full charge is in the system, you might want to check the electrical system out yourself. But your first step is getting the full charge of R134a in, then checking if the compressor is coming on, just look to see that the outer hub is drawn in when the AC is called for..Hope this helps.

Also, was the drier changed along with the expansion valve??

-------------------------
Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Edited: Tue January 13, 2009 at 7:07 PM by Chick

JerryHughes on Tue January 13, 2009 8:09 PM User is offlineView users profile

Quote
Originally posted by: Chick
That is why it doesn't hurt to get a second opinion and also ask questions. I realize you didn't know what questions to ask, but you're here now and we are getting more information.. If the compressor didn't start/engage then you might have an electrical problem, like a blown fuse, thermal switch problem if so equipped. If the shop "only" used their recycled refrigerant and didn't have a tank of virgin R134a on hand, run don't walk away from that shop. Before you give up on the compressor, bring it to a shop that specializes on AC repair and have it recharged correctly with virgin R134a, from a tank, with either a machine or scale and then ask questions if it doesn't work, like is the compressor engaging, is 12v getting to the coil, if not, were the fuses checked, relay etc.. After the full charge is in the system, you might want to check the electrical system out yourself. But your first step is getting the full charge of R134a in, then checking if the compressor is coming on, just look to see that the outer hub is drawn in when the AC is called for..Hope this helps.
Also, was the drier changed along with the expansion valve??

I really don't know if the compressor engaged or not. I did ask the tech if it was blowing cold air (a loaded question because in order to blow cold air or warm, it must have been running) and the tech said, "No". But he didn't say it ever turned on either. But if the tech said the compressor wouldn't pump over 50 p.s.i. on the high side, doesn't that mean the compressor turned on???

He also said he did check the fuses. Can a shop that specializes in A/C repair hook up the compressor, off a car, to see if it is functioning? The drier was changed but not the expansion valve. You see, I was replacing the compressor because the clutch went bad and since I have 161 K on the original compressor, I decided to change the compressor along with the clutch. No need to change the expansion valve. Thanks,

Jerry

Chick on Wed January 14, 2009 6:28 AM User is offlineView users profile

That would be my first step, find out if the clutch engaged, the refrigerant static pressure is very close to the outside temp, so at 60 degrees you static pressure would be close to 60psi (not running) and on a high side gauge, it might appear to be in the 50 to 60psi range, it would be easy to check for 12v at the clutch since it's a one wire, the compressor body is grounded on those I believe..a test light would have shown it.. But it can't pump less than the static pressure, so I doubt it was running...have that checked by another tech with the proper equipment as I stated above..Good luck..

BTW, you can check the clutch coil with an ohm meter, one lead to the wire and the other to the compressor body if it is a one wire system, should read between 3 to 4 ohms..Hope this helps.

-------------------------
Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Edited: Wed January 14, 2009 at 6:31 AM by Chick

JerryHughes on Wed January 14, 2009 10:36 AM User is offlineView users profile

Quote
Originally posted by: Chick
That would be my first step, find out if the clutch engaged, the refrigerant static pressure is very close to the outside temp, so at 60 degrees you static pressure would be close to 60psi (not running) and on a high side gauge, it might appear to be in the 50 to 60psi range, it would be easy to check for 12v at the clutch since it's a one wire, the compressor body is grounded on those I believe..a test light would have shown it.. But it can't pump less than the static pressure, so I doubt it was running...have that checked by another tech with the proper equipment as I stated above..Good luck..
BTW, you can check the clutch coil with an ohm meter, one lead to the wire and the other to the compressor body if it is a one wire system, should read between 3 to 4 ohms..Hope this helps.

Thanks Chick. I'll see if I can check those. If the compressor was okay, when the techs filled it and got no response, what would it take to get it going--right there and then? In the mean time, would anyone know where I could get some schematic drawings of the inside of this compressor? That would tell me if everything is assembled correctly. Thanks,

Jerry

Edited: Wed January 14, 2009 at 10:37 AM by JerryHughes

Chick on Wed January 14, 2009 2:14 PM User is offlineView users profile

Here are two pics of critical components to your compressor, first the refrigerant control valve, if it's clogged or broken, it won't pump. Next is that "plug" in the rear, sorry you can't read the tag, but it's used when the evap freezes on long trips, you can turn it to adjust. But you would either need to search the forum for this problem, as I "think" it's just a quarter turn, and damage to the compressor and the tech could occur if it's turned to much..So hopefully you didn't disturb it taking the rear head off.. It's not uncommon to have a bad control valve though, you tech should be able to detect this..




-------------------------
Chick
Email: Chick

---------------------------------------------

Freedoms just another word for nothing left to lose

JerryHughes on Wed January 14, 2009 4:26 PM User is offlineView users profile

Quote
Originally posted by: Chick
Here are two pics of critical components to your compressor, first the refrigerant control valve, if it's clogged or broken, it won't pump. Next is that "plug" in the rear, sorry you can't read the tag, but it's used when the evap freezes on long trips, you can turn it to adjust. But you would either need to search the forum for this problem, as I "think" it's just a quarter turn, and damage to the compressor and the tech could occur if it's turned to much..So hopefully you didn't disturb it taking the rear head off.. It's not uncommon to have a bad control valve though, you tech should be able to detect this..



Thanks for the pics, Chick. I doubt the refrigerant control valve is clogged or broken but the "plug" ------would that be where that large brass cylinder is located?? If so, do you know if the small pin on one end faces toward the center of the compressor? And when taking the end off, that whole brass cylinder fell out so I'm wondering if that could be damaged? And when I asked the shop what was wrong I was told that I didn't pay for a diagnosis, just to fill the system. It would cost me another $90 to have them tell me what's wrong, then they laughed. But if I could get a drawing I could see if there is anything loose, missing or assembled wrong maybe even order a new brass cylinder. Thanks again for the info and pictures.

P.S.----Come to think of it, when taking the two halfs of the compressor apart, the brass cylinder seemed like it was seated in the small end fairly well because it didn't drop out until I was putting that end down. And when I reassembled the brass cylinder, instead of making sure it was seated into the small end, I simply put the small pin that was coming out of one end of that brass cylinder into the hole you see in the large end of the compressor. If that is very sensitive to adjustment, maybe the brass cylinder should have been seated against the small end, then assembled?

Jerry

Edited: Wed January 14, 2009 at 5:43 PM by JerryHughes

JerryHughes on Thu January 15, 2009 6:11 PM User is offlineView users profile

Well I drove south to my favorite pick and pull and tried to take the end off one of their compressors. After being on the compressor for almost 12 years, the bolts just wouldn't come off, no matter how hard I tried. But I was able to take the large screw off the end of the compressor, that holds or adjusts that large brass cylinder. This was from a 96 instead of a 97 and appeared to be a copper spring instead of what I thought was a solid brass cylinder, at least on that year. Anyhow, I did assemble mine correctly with the small brass pin toward the center of the compressor so that's one big "if" I don't have to worry about. The more I think, the more I feel the techs who tried to get my compressor going just didn't know what they were doing. Will never know, huh.

Jerry

JerryHughes on Thu January 15, 2009 9:49 PM User is offlineView users profile

Would anyone know how to "start" or bring alive a compressor like mine if the tech is having trouble after filling?? Is there some little thing you should do if the compressor won't either respond or won't go over 50 p.s.i. on the high side??? Thanks for any info.

Jerry

JerryHughes on Sun January 18, 2009 10:55 AM User is offlineView users profile

Well, after all the wondering why the system wasn't good I found out that the gasket material I used for the compressor isn't any good! Tried to fill the system this morning and noticed it was leaking. So, I'm going to order the proper gasket from the factory and hopefully try to get it running all over again. The original gasket was "rubberized" and the one I replaced it with was more like "oily paper". Live and learn. Thank you all for your contribution and knowledge, it's much appreciated.

Jerry

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