Help me understand C3 A/C systems
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
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From: Springfield MO
St. Jude Donor '07
At least in my case, no A6 is involved. Even though it's a very early 77, somewhere along the way my car got an R4. It's going to be replaced with a serpentine R4, and I'm leaning towards just gutting my system and upgrading everything to the 77L-82 style.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
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From: Springfield MO
St. Jude Donor '07
Just that one low pressure switch, available at Autozone. You use the existing compressor power feed, run it through the switch and you're good to go electrically.
You'll also need the orifice tube, various O-rings, the appropriate oil, can't remember the misc little parts, not that there would be many, but nothing out of the ordinary.
Since you're replacing virtually everything you might consider a horizontal flow condenser, it'd save you from flushing your old one, and they're suppose to be more efficient. PM Zwede for a source on these, I used it and got one for around $115.
Also, it'd be a great time to do that C4 blower fan upgrade.
You'll also need the orifice tube, various O-rings, the appropriate oil, can't remember the misc little parts, not that there would be many, but nothing out of the ordinary.
Since you're replacing virtually everything you might consider a horizontal flow condenser, it'd save you from flushing your old one, and they're suppose to be more efficient. PM Zwede for a source on these, I used it and got one for around $115.
Also, it'd be a great time to do that C4 blower fan upgrade.
Burning Brakes
Joined: May 2004
Posts: 1,100
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From: belle plaine ks
better condensors available in the aftermarket
There is supposed to be better condensors in the aftermarket for r134a, that kind of look like cross flow radiators with a side tank. I can't think of the name of them [brain is slowly rotting
] but they are supposed way more efficient than previous models and really help the r134a systems out. Wait a minute it is coming to me, [after a google search] PARALELL FLOW CONDENSORS.
] but they are supposed way more efficient than previous models and really help the r134a systems out. Wait a minute it is coming to me, [after a google search] PARALELL FLOW CONDENSORS.
Burning Brakes
Joined: May 2004
Posts: 1,100
Likes: 3
From: belle plaine ks
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
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From: Springfield MO
St. Jude Donor '07
They have both low and high pressure switches listed. Where is that switch located? In the low pressure line?
Melting Slicks
Joined: Dec 2005
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Low pressure side. That picture is taken from overhead looking down the side of the evap box where the high pressure tube enters the box on the bottom. The switch and charging port above the switch are both on the low pressure side, the tube that comes out on top of the evap box and heads down to the accumulator.
Last edited by shafrs3; Jun 21, 2007 at 02:39 PM.
Race Director
Joined: Mar 2006
Posts: 14,112
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From: Florida
The low pressure switch controls the cycling. Get an adjustable one. It also stops compressor damage due to refrigerant loss.
The high pressure switch is required by the EPA for 134a conversions along with other things. You can search on the EPA website.
You can also add a thermostatic switch aka freeze switch to cut off the compressor in case of evaporator freezing.
Just make sure you have enough ports for the switches you want.
These switches don't have to be for GM, go to an auto ac supply and they have many generics.
http://www.epa.gov/ozone/title6/609/oneshop.html
The high pressure switch is required by the EPA for 134a conversions along with other things. You can search on the EPA website.
You can also add a thermostatic switch aka freeze switch to cut off the compressor in case of evaporator freezing.
Just make sure you have enough ports for the switches you want.
These switches don't have to be for GM, go to an auto ac supply and they have many generics.
http://www.epa.gov/ozone/title6/609/oneshop.html
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Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
The low pressure switch controls the cycling. Get an adjustable one. It also stops compressor damage due to refrigerant loss.
The high pressure switch is required by the EPA for 134a conversions along with other things. You can search on the EPA website.
You can also add a thermostatic switch aka freeze switch to cut off the compressor in case of evaporator freezing.
Just make sure you have enough ports for the switches you want.
These switches don't have to be for GM, go to an auto ac supply and they have many generics.
http://www.epa.gov/ozone/title6/609/oneshop.html
The high pressure switch is required by the EPA for 134a conversions along with other things. You can search on the EPA website.
You can also add a thermostatic switch aka freeze switch to cut off the compressor in case of evaporator freezing.
Just make sure you have enough ports for the switches you want.
These switches don't have to be for GM, go to an auto ac supply and they have many generics.
http://www.epa.gov/ozone/title6/609/oneshop.html
I think, for the moment, I'm just going to install an A/C delete pulley and start assembling what I need for the switchover to the more modern system.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
The high switch goes anywhere between the compressor and the oriface tube. Have the hoses made up with the required ports.
The low switch or cycling switch goes on the suction side.
Make sure all service ports are accessible to gauges when finished.
The freeze switch just wires into the ac clutch power and the sensor sits against the evap coil. Cheap switch, good insurance. Can also be used in place of a cycling switch, but not recommended.
I'm Batman
Just mount your r4 compressor and don't power the clutch. It will act as a pully then. Make sure the compressor ports are sealed off.
The low switch or cycling switch goes on the suction side.
Make sure all service ports are accessible to gauges when finished.
The freeze switch just wires into the ac clutch power and the sensor sits against the evap coil. Cheap switch, good insurance. Can also be used in place of a cycling switch, but not recommended.
I'm Batman
Just mount your r4 compressor and don't power the clutch. It will act as a pully then. Make sure the compressor ports are sealed off.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
The high switch goes anywhere between the compressor and the oriface tube. Have the hoses made up with the required ports.
The low switch or cycling switch goes on the suction side.
Make sure all service ports are accessible to gauges when finished.
The freeze switch just wires into the ac clutch power and the sensor sits against the evap coil. Cheap switch, good insurance. Can also be used in place of a cycling switch, but not recommended.
I'm Batman
Just mount your r4 compressor and don't power the clutch. It will act as a pully then. Make sure the compressor ports are sealed off.
The low switch or cycling switch goes on the suction side.
Make sure all service ports are accessible to gauges when finished.
The freeze switch just wires into the ac clutch power and the sensor sits against the evap coil. Cheap switch, good insurance. Can also be used in place of a cycling switch, but not recommended.
I'm Batman
Just mount your r4 compressor and don't power the clutch. It will act as a pully then. Make sure the compressor ports are sealed off.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Try this guy JW at jw@amcmfg.biz
800-900-9560
He can set you up with a Sanden 10 cu in (original vette a6 was a 10) and probably the mounting adapters. If not , they are easy to make.
800-900-9560
He can set you up with a Sanden 10 cu in (original vette a6 was a 10) and probably the mounting adapters. If not , they are easy to make.
Instructor
Joined: Nov 2006
Posts: 119
Likes: 2
From: Baton Rouge La
Sorry to insert my question into somebody else's thread, but 2 days ago, the only switch that worked on my 75 air conditioner control was the intensity??? switch on top of the face. That turned the air on and off. Now, only the wheels being turned to Max A/C turns the air on (or off if turned to Off). Is my switch just bad?
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Dredging this one back up...
My 82 evaporator has some sort of valve doohickey in the smaller line. What is this, and do I need to replace it when re-assembling the system? Is it something that I need to change for the R134a conversion?
My salvaged parallel-flow condenser (from a Dodge van) has a switch in the hard line (I assume it's the high-pressure line?). I'm guessing that it's a high-pressure cutoff switch? The evaporator has the low-pressure switch built into the large line.
I flushed the evaporator and condenser tonight. What's the best way to seal off the fittings until I'm ready to re-assemble the A/C?
My 82 evaporator has some sort of valve doohickey in the smaller line. What is this, and do I need to replace it when re-assembling the system? Is it something that I need to change for the R134a conversion?
My salvaged parallel-flow condenser (from a Dodge van) has a switch in the hard line (I assume it's the high-pressure line?). I'm guessing that it's a high-pressure cutoff switch? The evaporator has the low-pressure switch built into the large line.
I flushed the evaporator and condenser tonight. What's the best way to seal off the fittings until I'm ready to re-assemble the A/C?
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
1) Is it a valve or a port, can you post a picture of it?
2) Good bet it's a hp switch, you can use it in your system if so.
3) Cover the ends to keep out the dirt, a rubber plug/cap, tape, anything would work that's not dirty itself.
2) Good bet it's a hp switch, you can use it in your system if so.
3) Cover the ends to keep out the dirt, a rubber plug/cap, tape, anything would work that's not dirty itself.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Where can I find rubber caps in sizes that will fit the lines?
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
I've collected various rubber and plastic caps & plugs over the years for just this reason but the HELP section at the local auto parts store has some vacuum plugs and caps you might be able to use, or get some vinyl electrical tape and wrap the open ends. Summit also has some from various manufacturers, search for "vacuum plugs".
Last edited by shafrs3; Jul 11, 2007 at 04:24 PM.