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Old 04-10-2018, 04:56 PM   #1
zedjr10
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Replacing AC compressor

I got a 92 accord ex coupe and i am soon to be replacing my AC compressor. It was converted to r-134a before i bought car. So is this just a simple replacement of the compressor. It seems pretty str8t froward but wanted to ask. Am going to get a denso unit. Is there anything i need to consider that isn't in the replacement guide. Also was wondering why shops want soo much dollars for this. 420 bucks one shop wants.
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Old 04-10-2018, 05:01 PM   #2
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Simple to do, like an ALT. They charge that much because you need special tool to fill the AC with refrigerant and have to know what you are doing. I'm guessing their price was including hardware too (the AC compressor).
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Old 04-10-2018, 07:29 PM   #3
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I just cost me $142 for an evacuate and recharge (with about 45 minutes in between so I could go home and replace the pressure switch). I believe it is technically illegal to deliberately release the Freon to the atmosphere, so the system should be evacuated prior to changing the compressor (unless it has all leaked out already).
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Old 04-11-2018, 04:22 PM   #4
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Quote:
Originally Posted by fleetw00d View Post
I just cost me $142 for an evacuate and recharge (with about 45 minutes in between so I could go home and replace the pressure switch). I believe it is technically illegal to deliberately release the Freon to the atmosphere, so the system should be evacuated prior to changing the compressor (unless it has all leaked out already).
It is also technically illegal to drive 56 in a 55 and cross the street in an unmarked crosswalk.
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Old 04-11-2018, 04:53 PM   #5
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I knew a guy who did it for big rigs, and he did my car once and explained it to me. As technical as I am he confused the heck out of me in regards to low and high pressures, and what to look for, etc. You also need a proper AC filling machine which can vacuum the lines out first to create a low pressure, remove moisture (which is why you need to replace the drier), then introduce the AC refrigerant to it. A skilled tech can also tell you why it may not work if something goes wrong (drier, evaporator, leak detection, or other). There's a lot that goes into it especially when your AC works but is not cold. It's not as simple as "filling something". Also when changing the AC unit you may introduce moisture to the system which is bad.

Take a look at this page. If any of it confuses you best to stay away.
http://www.instructables.com/id/How-...r-Conditioner/
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Old 04-11-2018, 10:21 PM   #6
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You need a vacuum pump, thermometer, and a gauge set minimum. System pressure is relative to ambient temperature. Higher temps = higher system pressure. Say it’s 100 degrees outside, that high pressure line can reach 300psi.

Gauge readings tell you what could be a potential problem within the system.

If both low and high readings are too high, you’ve over charged the system.

Too low of readings on low/high usually means there is a slow leak, or the system needs a charge.

A lower low with a higher high means there’s a blockage - which in our case is the expansion valve.

A high low side with a low high side points to compressor failure.

If you’re hell bent on doing it yourself, the cost of a pump/gauge set is already just as expensive as getting it done at a shop. That being said, you can do it.

1.Evacuate the system. Legally obviously. Don’t be a scumbag.

2.Hook up the vacuum pump to remove all moisture and determine if you have a leak or not. System should hold 30inHG - in your case it won’t right?

3.Do your repairs. Compressor, expansion valve, drier, o-rings.

4.Confirm your repair is good. Put vacuum on system to see if it holds.

5.Add ester oil to factory specs. You can do this with your gauge set using the middle line. Just measure the amount of oil needed, and use the vacuum within the system to suck up the oil. 1990-1992 need 4oz of oil where 1993 models need 4.5oz.

6.Charge with r134 to 0.7 of factory specs. In the CB7, 1990-1992 need 32oz of r12 which means 22.4oz of r134. 1993 models need 30oz of r12 which means 21oz of r134.

If everything is good, start the car and let the AC run on high for about 5 minutes to regulate with your thermometer in the vent. Functional systems should put out 45* or colder air.

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Old 04-13-2018, 11:27 PM   #7
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Quote:
Originally Posted by zedjr10 View Post
It is also technically illegal to drive 56 in a 55 and cross the street in an unmarked crosswalk.
Yeah, I know. You'll do whatever you're comfortable with. Like I said, if it has all leaked out, then the initial evacuation to remove any remaining refrigerant is not a big issue, but you'll still need to pull a vacuum to determine if there is a leak prior to attempting to fill it.

I have been able to charge a repaired system by rigging a T and shut off valve into the charge hose. I have a pump to pull a vacuum on the system before introducing the refrigerant, close the valve to isolate the system, make sure it holds vacuum, then refrigerant can be introduced.

Last edited by fleetw00d; 04-13-2018 at 11:34 PM.
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Old 04-10-2018, 07:30 PM   #8
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You NEED to replace the expansion valve & drier as well when replacing compressors. Get ester oil, and fill refrigerant to .7 of the factory r12 capacity if using 134.
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Old 04-10-2018, 11:37 PM   #9
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Quote:
Originally Posted by F22Chris View Post
You NEED to replace the expansion valve & drier as well when replacing compressors. Get ester oil, and fill refrigerant to .7 of the factory r12 capacity if using 134.
I don't see that in the replacement guide. Where would i find a guide on that?
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Old 04-11-2018, 05:30 AM   #10
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No guides around that I am aware of but he's right. You need to eliminate the old contaminated stuff. I've seen people not do it but it's not the proper way to do it. What i was talking about was the compressor, gauges, and know-how to fill the system with refrigerant. Only a certified technician should do it.

But still sounds like you need to shop around for a lower price.
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Old 04-11-2018, 01:45 PM   #11
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Quote:
Originally Posted by Raf99 View Post
No guides around that I am aware of but he's right. You need to eliminate the old contaminated stuff. I've seen people not do it but it's not the proper way to do it. What i was talking about was the compressor, gauges, and know-how to fill the system with refrigerant. Only a certified technician should do it.

But still sounds like you need to shop around for a lower price.
Am going to do it myself. It can't be that hard to fill system and anything other to do. I don't trust mechanics anymore at all. It is not like they go to special refrigerant school for 4 months or something. They was probably shown how to do it by a workmate. The coolant in the system now is at 0 psi on low side port(all leaked out). I'll try to find some guides for this on youtube.
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Old 04-10-2018, 11:32 PM   #12
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Quote:
Originally Posted by Raf99 View Post
Simple to do, like an ALT. They charge that much because you need special tool to fill the AC with refrigerant and have to know what you are doing. I'm guessing their price was including hardware too (the AC compressor).
it was 620 including compressor. What special tool? DO you mean the same one i recharge it with? If not can i get a loaner from parts store?
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