I am reconstructing a 70 Skylark Custom and have all of the A/C and heater parts cleaned up, the firewall painted, the outside A/C box painted and a complete (I think) gasket set. I want to reinstall most of the inside and outside A/C components (enough so that I have heat in the car) before I put the engine back in, but I am reasonably certain that I will have to take the outside A/C box back apart when I really want the A/C to work. Has anyone installed studs or floating fasteners on either side to make it somewhat easier to get apart again? The condition of the A/C box on my car when I bought it was pretty messy. It was missing about 1/2 of the fasteners (it even appears that the holes in the firewall are too big already for the fasteners that were there) and was held to the firewall with instant insulation spray (Great Stuff I think is the name). The previous owner was also generous with the the RTV in other gaps and the hole in the A/C box. These are a couple of the reasons why my confidence is pretty low regarding the "innards" of the A/C box. Thanks for your help...Gary
Hmm, your post has been here for quite a while and nobody replied. If it were my vehicle, I would fully assemble everything in the evaporator case and under the instrument panel and be done with it. Just cap the AC line connections at the firewall until you install the rest of the refrigerant loop (compressor, lines, etc.) If you clean and reseal everything the first time there should be no reason to remove the evap case again. I seem to recall that the holes in the firewall were large and the fasteners used big washers. This would allow proper alignment during assembly. Good Luck If you need help getting the AC up and running, feel free to contact me when the time comes. I'm in Lorain County, about 40 miles from you. I get over east of Cleveland about once or twice a month. As a matter of fact, I was in Willoughby last week.
Thank you for the reply. I saw a lot of views, but no one had replied. I am starting the reconstuction on Monday and it will be entertaining to see how many unexpected issues I run into. It only had about 1/2 the fasteners on it when I took it apart and I think the ones that at one time threaded into the firewall have enlargened the holes enough that I will either have to back them up with something threaded on the inside or bump up the thread size. This will be all part of the adventure. Thank you for the reply and the offer to help. This Buick Community is outstanding! Gary
My first thought is that a/c systems are never easy to work on. With that in mind and the fact that you have the engine out of the car right now, do whatever you have to do to get it done now. I've always believed in doing it right the first time so it will not have to be done over later. You will be much happier about it. Bill
It only had about 1/2 the fasteners on it when I took it apart and I think the ones that at one time threaded into the firewall have enlargened the holes enough that I will either have to back them up with something threaded on the inside or bump up the thread size. Aahh, ok. I was thinking that there were studs on the evap case and nuts/large washers holding it to the firewall. You're talking about sheet metal screws right into the firewall. I wonder if you could attach clip-nuts or tinnarman nuts on the inside of the stripped holes to run the fasteners into? Maybe epoxy them into place?That would make assembly easier and allow you to use the proper size fasteners.o No: That's just the first idea that popped into my head. Edit: Ditto on what Golden Oldie 65 said. That's what I was trying to say earlier.
Bill, I am trying to do everything as right as possible the first time. I am not a big fan of doing things twice, but this is my first project, so I know that there will be some things that I will hose up along the way. I think the only questionable component is the evaporator core. Do you know if there is a way to test this little monster before I reassemble it? Thank you...Gary
The tinnerman or clip nuts sound like they may be the solution. I am going to "mock up" the assembly of both halves of the heater and A/C box to a cardboard "firewall" so I can better visualize how this all goes together and then go to the hardware store and stare at some possible fastener solutions. Thanks again for the suggestions...Gary
If there is any doubt I would just remove it and take a good look at it. Evaporators rarely go bad because there are no moving parts and it is not subject to road dirt and debris, but it if looks like it hasn't been fastened in properly, if there has been any rubbing on it or anything else that has had opportunity to cause it damage then it would be good insurance to just replace it. I don't know of any way to test an evaporator without pressure in the system. Possibly put it in a big bucket of water, seal one end and pressurized the other end. I've never tried this so it's just an idea, but if you decide to do it then go easy. If there is a leak it won't take much air pressure to find it. I have an extra a/c box complete with the evaporator that I believe is in nice shape. I haven't actually looked it in awhile but I'll get it out and take a look at it today. If you need it maybe we can work something out. Bill
Yes, pressure testing in a bucket of water is the way to go. You can go up to about 150-175 psi on an evaporator, but you don't need much more than 40-50. It's actually pretty common for them to be corroded and leaky from all of the dirt and debris that gets pulled into the evaporator case over the years. There is no air inlet filter like on many modern cars, so the incoming dust and dirt gets plastered to the nice wet evaporator and holds moisture. Another common concern is internal corrosion. If AC parts are left open for a long period of time, the raw aluminum on the inside surfaces can corrode badly. Take a blow nozzle and blow through the evaporator. If you get any white dust or other debris from the pipes the evaporator MUST be replaced or the oxidation will break loose and cause restrictions in the metering devices. The same thing applies to the condenser and metal lines. Solvent flushing won't help with this. It will only remove the loose debris leaving more to detach later and damage the system.
Since this is my first project undertaking, I think I am allowed to plead ignorance at least once (a day). I took some pictures of the patient, can you advise me on which lines I should block and which one(s) I should inject the air into? The first image (evap core1) has the 4 lines numbered. I also took pictures of each side. I did blow out the coils pretty well and yes, the box was full of all kinds of junk (leaves, dirt, etc). Upon closer inspection, it does look like there is more junk in the coils, I imagine that should come out once I put it in the bucket to pressure test it. If it fails this test, I will either be shopping for a replacment or an A/C delete box. Thank you both for the excellent advice thus far. I am on vacation all week and was hoping to drop the motor back in on Friday, but I need to solve this dilema first. Not that you should be surprised, but this isn't the only hiccup I have encountered. Thanks again...Gary
Plug #2, #3, and #4 and shoot some air into #1. Not sure if you would even get any air exiting the expansion valve but I would plug them all tight just so I wouldn't get water inside anything. Bill
That evaporator looks pretty good in the pics. I don't see any corrosion. That's a really good sign. Blow as much of the crud out of the fins as you can before you get it wet using a blow gun and compressed air. You will need to remove the Expansion valve or TXV (the part that contains #2). You can leave it off until you get ready to assemble the AC lines and such later. The sensing bulb is clamped to the hose under the blob of tacky tape. Take note of where it's clamped. We'll call the fitting that attached to the TXV #2 now. #3 is part of the TXV and not plumbed into the evaporator. First, blow compressed air through #1 and hold your thumb over #2 to build some pressure. "Pop" your thumb off and look for debris or white dust when the air blows out. If the air is clean or you get some oil, the inside should be ok. Now do the same thing while putting air into #1 and blocking #2. Air will also come from #3, make sure no debris comes out of that one either. Now, cap off #3 and #2 as tightly as possible. You may have to get creative with some heater hose or fuel line. Using a rubber tipped blow gun, apply about 30-50psi to #1 and submerge the core in water. You can add some dish soap to the water to break the surface tension. Swish it around a bit to dislodge air trapped in the fins. Now, watch closely for a stream of bubbles coming from anywhere on the core, tubes or welded connections. Look close, a tiny leak will make tiny bubbles and can be hard to see. If you don't see bubbles, the core is ok. The last step is to solvent flush the core. Just pour about 6 ounces of lacquer thinner or similar non-residue solvent into the tubes. Cap the tubes and shake it arouns some. Then blow compressed air through all of the tubes until there is no liquid left inside. Cap off the lines to keep out moisture and dirt, then install the core into the evaporator case. Hope this helps.
Gentlemen, Thank you again for your guidance on my A/C adventure. I concocted a set up to do the pressure testing this evening and I think the results are questionable. I was not able to completely seal the ends, but I think I had them good enough to see any bubbles. The first pass was a bit of a disaster as I put too much detergent into the 10 gallons of water (I didn't think it was that much, but once I put the core into the water, there were suds everywhere). Take 2 - no detergent and I rinsed the core, but there was enough residual detergent to give the desired effect. I didn't really see any bubbles, but once I flushed it with the lacquer thinner, the stuff that came out looked pretty bad. I flushed it 3 times and the cup you see in the attached picture has what came out on the third pass. The first two passes looked similar and it didn't look like it was improving. The interesting thing is that I put the thinner into hole 1 and swished it around and it will come out either hole 1 or 3, but not 2. I put thinner into 2, but it will not come out of 2, only 1 or 3. Should I continue trying to flush it or is this an indicator of other bad stuff? Thanks again for the help...Gary
Are you blowing it out with compressed air or just rinsing it? You'll need a few good, long blasts of air to get it all out and dry up the thinner.. The goo in the cup looks like old, contaminated refrigerant oil. Look close and see if there are any solids. Especially look for debris that looks like oxidized aluminum. If all you see is the grundgy oil, you'll be ok. All of that oil probably protected the low points in the core from collecting moisture and corroding. Keep flushing. If you didn't see any leaks, I'd say that core will be fine.:TU: Oh, look close at the ends of the tubes, especially around the ring. Make they're they're not damaged. It didn't look like it in the pictures, but...
I was just rinsing it. I did not blow any more air through. I ran out of thinner and will get some more in the morning. I will continue to rinse and blow it out this time. I didn't see any solids in the cup, it just looked like old oil. Was the issue about not getting anything to come out of hole number 2 anything to be concerned about? Thank you...Gary
Find an assemblly or service manual it has nice expoded views of the box. To bad you were not closer. Local yard has 5 Skylarks with AC and all parts. I juts took one apart to get at the defroster duct under the dash that would not comeout without removing fender and AC Box and heater box under the dash.
Gary, as you can see, i am at the same stage you are with the a/c, did you replace the "o" rings on the piping connections fittings and if so where did you buy them from or are they just a typical o rings that are in a generic o ring kit? i'll bet the a/c on my car wasn't working very good for the last owner... Cheers, Gord
Gord, You must have been reading my mind. As I was flushing and blowing out the evaporator core, I noticed how ugly looking the o-ring was. I was almost afraid to pull it out, but I think I should before I start re-assembly. Maybe someone will read this thread and give us both the answer on the source for this seal/o-ring. I had to take a detour from this part of the project yesterday to drill some new holes in my flex plate for the stall convertor. Gary
not really reading your mind, but we all go through the same stuff eventually. there are 4-6 o-rings that should be replaced, i'll do some digging and see what i can find for a supplier, but hopefully somebody will chime in like you said. ttyl Gord
