Help an A/C neophyte
Thread Starter
Melting Slicks
Joined: Jun 2009
Posts: 2,709
Likes: 3
From: Savannah GA
Help an A/C neophyte
I'm getting the late 77 project ready for the engine drop by reinstalling everything under the hood which will be a PITA once the motor's in the hole. This car came to me completely disassembled so I don't even have the memories of taking it apart to work from. I have replaced the heater core and evaporator and wish to add the accumulator/dryer next since it is buried in the fenderwell. Are there supposed to be o-rings on the fittings both sides of this thing? If yes, do the o-rings go on the small lip flanges inside the holes, or at the thread root of the "nut"? What size/durometer and material is required? I'm not there yet, but what and where at the condenser as well? Thanks all!!!!!
Drifting
Joined: Jun 2005
Posts: 1,523
Likes: 1
From: grand prairie texas
It has been years since I have installed the accumulater on my 77 but if I remember correctly on thos big nuts I dont think they are supposed to have o rings. They are a pain in the *** to tighten I had to use a crows foot to tighten them
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
The tip of each line will have a ridge crimped about 1/4" back. Lube the o-ring with A/C oil and slide one onto each line,up to the ridge, then tighten the nut. You should be able to find an assortment of a/c o-rings at your local parts store.
Thread Starter
Melting Slicks
Joined: Jun 2009
Posts: 2,709
Likes: 3
From: Savannah GA
I see we have divergent opinions....my system uses the Harrison "late" compressor and an orifice tube, not the earlier Frigidaire with VIR. Tie breaker anyone? 
Also on the orifice tube; where does that go exactly, and which one is best recommended for R134? Happy Memorial Day!
Also on the orifice tube; where does that go exactly, and which one is best recommended for R134? Happy Memorial Day!
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
75 is correct and the local parts stores will have orings that work for both r12 and 134.
You may want to put a very little bit antisieze on just the threads and no need to tighten them excessively.
For the oriface tube, follow the bottom evaporator tube and you will see an indentation just under the connection. The OT stops at that indentation.
You may want to put a very little bit antisieze on just the threads and no need to tighten them excessively.
For the oriface tube, follow the bottom evaporator tube and you will see an indentation just under the connection. The OT stops at that indentation.
Racer
Joined: Sep 2009
Posts: 437
Likes: 3
From: Alvin Texas
I would assemble it with the same orifice tube (use a new one) and an accumulator suitable for R 134a, be sure to reverse flush the condenser with an A/C flush, there usually a collection of crud in it. Blow out what oil is left in the evaporator with compressed air, (Not all will come out no matter what you do), use PAG oil in the system. Pull a vacuum on the system for at least 30 minutes after max vacuum is attained the longer the better. When you charge the system place a fan in front of the car directing the air to flow across the condenser and radiator. When charging, put in enough freon to attain a high pressure that is equal to 2X outside temp + about 15*. If OAT is 90* the pressure would be around 200*. The compressor should cycle at about 25# if it doesn't adjust the screw between the pressure switch ccw to get that pressure. Too low and the evap will freeze. Inside temp @ the outlets should be 38*-48*.
Thread Starter
Melting Slicks
Joined: Jun 2009
Posts: 2,709
Likes: 3
From: Savannah GA
Thank you all for the primer! '75... please don't take offense, I simply wanted confirmation before I made an error in reassembly. Thank you Noonie for that confirmation, and the scoop on the tube. Bpassmore this system will be essentially new... new evaporator, new dryer, new flex lines, rebuilt compressor and a brand new AC Delco condenser. New low pressure switch and (white???) orifice tube. I've flushed the hard line running along the fenderwell too. Some Reflectix is on the way... It gets HOT here (95 presently) and I wish to cruise in comfort when I finally get to the maiden voyage. Is there anything else I should consider doing while the interior is gutted and the engine compartment empty???
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Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Have a look at the rear of the hood for the condition of the weather stripping. If it's in poor shape, mashed, missing or otherwise, be sure to replace with new. This strip prevents hot air from the engine compartment from entering the duct work in the cabin.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Thank you all for the primer! '75... please don't take offense, I simply wanted confirmation before I made an error in reassembly. Thank you Noonie for that confirmation, and the scoop on the tube. Bpassmore this system will be essentially new... new evaporator, new dryer, new flex lines, rebuilt compressor and a brand new AC Delco condenser. New low pressure switch and (white???) orifice tube. I've flushed the hard line running along the fenderwell too. Some Reflectix is on the way... It gets HOT here (95 presently) and I wish to cruise in comfort when I finally get to the maiden voyage. Is there anything else I should consider doing while the interior is gutted and the engine compartment empty???
Melting Slicks
Joined: Mar 2009
Posts: 3,126
Likes: 15
My new R12 orifice is white. The old was black. There is an o-ring on every connection. Some of the new ones were green and some blue. The old ones were black. I count eight, including the two on the back of the compressor. Definately a little compressor oil on the o-rings and anti seize on the threads. Smoothes out the tightening process. mike...
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
No offense taken.
This would be a good time to check the fresh air door located at the passenger side of the wiper tray. My 75 is stuck closed which is ok with me, but my kids 76 has it stuck open, so it's always using outside air and not recirculating on max ac.
This would be a good time to check the fresh air door located at the passenger side of the wiper tray. My 75 is stuck closed which is ok with me, but my kids 76 has it stuck open, so it's always using outside air and not recirculating on max ac.
Thread Starter
Melting Slicks
Joined: Jun 2009
Posts: 2,709
Likes: 3
From: Savannah GA
Jud... will do. My new weatherstrip kit from Willcox has that part in it and I'll be sure to refresh. Noonie... I bought my compressor from a fellow forum member a couple years ago before I knew any better; it is "fresh" so I guess I'll use it for now. 75... I'll need to wait until I can live test the circuits but I've printed this thread so I will have a checklist later. Thanks. Keep the suggestions coming! Mark