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Re: Suburban A/C fix + Vintage Air?
Ok, now I'm scratching my head.
So I believe this to be a low pressure switch, can anyone confirm that? Can I also use that unused "port" (with the black cap) for a high pressure trinary switch? https://photos.smugmug.com/VehiclesO...IMG_9607-L.jpg |
Re: Suburban A/C fix + Vintage Air?
That is indeed the LPCO switch.
The black capped fitting is the low pressure manifold gauge service connection. The HPCO has to be in the high pressure side of the system. Usually right off the compressor in the high side line. |
Re: Suburban A/C fix + Vintage Air?
Holy Cow, I ordered a Trinary switch from Summit Racing YESTERDAY and it's in the mailbox already. Less than 24 hours. Crazy.
https://photos.smugmug.com/VehiclesO...IMG_9621-M.jpg Here we go! Brackets for the condenser. I took the "install kit" cut it and bent it to use existing hols in the core support. https://photos.smugmug.com/VehiclesO...IMG_9609-M.jpg https://photos.smugmug.com/VehiclesO...IMG_9610-M.jpg Final of the Condenser bracket install. Getting this all in there was the hardest part so far. https://photos.smugmug.com/VehiclesO...IMG_9618-M.jpg |
Re: Suburban A/C fix + Vintage Air?
The moment of truth:
https://photos.smugmug.com/VehiclesO...IMG_9622-M.jpg The first crimp! https://photos.smugmug.com/VehiclesO...IMG_9624-M.jpg Now like 45 to go! https://photos.smugmug.com/VehiclesO...IMG_9625-M.jpg Mocking up: https://photos.smugmug.com/VehiclesO...IMG_9626-M.jpg Routing the hoses is harder than I thought it would be. I don't want it to look like a cluster. Every combination looks weird! https://photos.smugmug.com/VehiclesO...IMG_9631-M.jpg |
Re: Suburban A/C fix + Vintage Air?
Running the lines and mocking things up before "the final crimpdown!"
https://photos.smugmug.com/VehiclesO...IMG_9636-M.jpg https://photos.smugmug.com/VehiclesO...IMG_9637-M.jpg https://photos.smugmug.com/VehiclesO...09824398-M.jpg |
Re: Suburban A/C fix + Vintage Air?
This gives me feelings of optimism:
https://photos.smugmug.com/VehiclesO...IMG_9640-M.jpg Drain Hole from "kustom drain holes express" https://photos.smugmug.com/VehiclesO...IMG_9643-M.jpg yes, buy some extra length hose, just in case! https://photos.smugmug.com/VehiclesO...IMG_9644-M.jpg Aaaaand Here is the final mock up before all the crimpin' goes down. Might not win a trophy, but if she blows cold, well, winning! It looks like those hoses touch the belt in this pic, but there is plenty of room. https://photos.smugmug.com/VehiclesO...IMG_9650-M.jpg |
Re: Suburban A/C fix + Vintage Air?
Carry on my wayward son...
https://photos.smugmug.com/VehiclesO...IMG_9657-M.jpg https://photos.smugmug.com/VehiclesO...IMG_9666-M.jpg https://photos.smugmug.com/VehiclesO...IMG_9667-M.jpg https://photos.smugmug.com/VehiclesO...IMG_9658-M.jpg https://photos.smugmug.com/VehiclesO...IMG_9659-M.jpg Ok so all crimped up and read to rock and roll. Now for the bad news: Never was able to pull more vacuum than this. https://photos.smugmug.com/VehiclesO...IMG_9665-M.jpg And after I shut it off, I lose vacuum. https://photos.smugmug.com/VehiclesO...IMG_9676-M.jpg https://photos.smugmug.com/VehiclesO...IMG_9671-M.jpg So I have a leak in all my glorious crimps and connections. What next? |
Re: Suburban A/C fix + Vintage Air?
Seems the smart thing to do is to put some compressed air into the system and spray some soapy water the connections.
Here is a video that shows the procedure I used https://www.youtube.com/watch?v=J6DSpx1V3Ms Basically you put a rubber tipped air gun where the yellow vacuum pump hose goes, and pressurize the system, then with a spray bottle of soap and water get to squirting on your joints. The great thing about air leaks is that you can *hear them! So I found the leak! https://photos.smugmug.com/VehiclesO...IMG_9682-M.jpg This puppy was hissing air. Now, no one in their right mind would put a junk yard Low Pressure Cut Off switch on their brand spanking new AC system...would they??? Next up, we put it back on the vacuum pump and see if it holds! Fingers crossed. |
Re: Suburban A/C fix + Vintage Air?
Hang in there! It's probably something simple. Check all your fittings for O rings and damaged O rings as well as switches.
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Re: Suburban A/C fix + Vintage Air?
Make sure the Schraeder valve on the service port that's on the side of the accumulator isn't leaking.
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Re: Suburban A/C fix + Vintage Air?
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Edit: I was looking at the mechanical (non-hydraulic) mastercool one, but decided on this one. I'm glad I did because at some point you will need to make a crimp in a hard to reach place and the hydraulic one is the no-brainer choice as it does not need to be held in a vise. |
Re: Suburban A/C fix + Vintage Air?
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Does this look right? https://photos.smugmug.com/VehiclesO...IMG_9686-M.jpg Upper left Black wire: This is the Original ON green wire that passes through the Low Pressure switch. This wire originally would have plugged directly to the compressor. Upper right blue wire: To terminal 86 (trigger) of the Fan relay. Lower left blue: Keyed power. Lower right black: to 86 (trigger) of Compressor relay. Thanks for the help on this! I have a new LPCO on order, I'm getting close! |
Re: Suburban A/C fix + Vintage Air?
My fan relay has a part number on it. I went and bought another one just to have the instructions.
"Green Wire (Air conditioning override) ... attach the green wire to the A/C Clutch wire" https://photos.smugmug.com/VehiclesO...IMG_9700-L.jpg If I understand this correctly this means when the green wire gets power, the fan gets triggered. (you can't actually see where the wires are connected as they are epoxied together. If this is true then I don't have to hook up the blue wires of the Trianary switch. Key On: I just connected the Green wire to the battery assuming that putting voltage to that wire would trigger the fan to come on. Nothing happened. I'm kinda lost on this wiring setup. Here is why my jumble jangle switch looks like. I need to spend some time and clean up all the janky wiring the PO left behind. https://photos.smugmug.com/VehiclesO...IMG_9697-M.jpg |
Re: Suburban A/C fix + Vintage Air?
I had a couple issues getting the right LPCO switch, and once I got it, I had trouble getting it to seal. Pro Tip: hand tight only!
Also the rear blower was hitting the case so I had to pull that down and align the motor better. First I was going to trim it: https://photos.smugmug.com/VehiclesO...IMG_9692-M.jpg https://photos.smugmug.com/VehiclesO...IMG_9694-M.jpg The fix was to undo the one bolt on the fan clamp and slide it over a bit so the blades fit in the case properly without rubbing. Test before you hang it! https://photos.smugmug.com/VehiclesO...IMG_9695-M.jpg Otherwise system is now holding pressure, today I'm getting the wiring sorted out, and hopefully put some charge to it! |
Re: Suburban A/C fix + Vintage Air?
Yeehaw!
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Persistence!
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Thanks for the encouragement fellas!
This seems really simple when I draw up this pic, but it took me a while to get there. Thanks to @hatzie for suggesting this wiring strategy of using a relay for the compressor! Not shown is the relay and switch for the rear AC Blower. https://photos.smugmug.com/VehiclesO...C_Wiring-M.jpg This means the wiring is now hooked up, and I can potentially run the system today. Is today THE DAY? I'm sure there are about 30 things that need buttoning up, but I'm going for it! Here is some wiring for your enjoyment, not many folks appreciate a good crimp! https://photos.smugmug.com/VehiclesO...IMG_9712-M.jpg A little wire loom makes those wires look a lot better: https://photos.smugmug.com/VehiclesO...IMG_9709-M.jpg This is when you know you should step away from the heat gun. https://photos.smugmug.com/VehiclesO...IMG_9708-M.jpg |
Re: Suburban A/C fix + Vintage Air?
FANcy!
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Re: Suburban A/C fix + Vintage Air?
I need to add about 3 oz of PAG oil to this system.
I arrived at that number by looking at the manual and talking to the sales/tech, the original system (with dual AC!) had 3 oz more then the since evap system. So assuming the compressor has enough oil in it for a single AC system, we then will add 3 oz for a dual. How should I add the oil? I need to pull a vacuum on it anyway, so it's open, now. I'm seriously considering opening one of the rear lines and just pouring 3 oz in. Considering the rear lines are 15 feet long, I don't think it should be a problem. |
Re: Suburban A/C fix + Vintage Air?
Wiring done enough to run the system
https://photos.smugmug.com/VehiclesO...IMG_9718-M.jpg Only add to the high pressure (discharge) side or your compressor will suck in liquid oil and the sun will stop spinning in the sky! https://photos.smugmug.com/VehiclesO...IMG_9720-M.jpg Make sure you have a good assistant! https://photos.smugmug.com/VehiclesO...IMG_9721-M.jpg Right now, we are pulling a vacuum and double checking Last Time for leaks! |
Re: Suburban A/C fix + Vintage Air?
Oh man, I can barely breath... My virtual finger are crossed for you.
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Re: Suburban A/C fix + Vintage Air?
I would recommend drawing up a schematic of the wiring so when you come back to it in 3 years you can figure out what you did...
As an occasional buyer... It's a selling point to have a wiring diagram for any hot rod. Even some custom shops will refuse to work on electrically modified vehicles without documentation because they have to create said documentation as they go so they can figure out what went wrong. That kind of work is time consuming and most people don't want to pay shop rate for that kind of tedious time consuming work. |
Re: Suburban A/C fix + Vintage Air?
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Here are all the changes I made to the system. Hatzie gives good advice. https://photos.smugmug.com/VehiclesO..._diagram-M.jpg I had to relocate my fuel pressure regulator which WAS where the AC is now. It took me an hour to figure out where to put it. At this point I realized I needed to just quit for the day. I asked my 11 year old buddy for some advice. And I mounted it to the firewall. Still need to 1. Run the inlet fuel line. 2. Run the wire for the rear fan 3. Vac the system for an hour 4. Hook up rear fan switch 5. Fire it up! |
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Re: Suburban A/C fix + Vintage Air?
Per the manual the charge required for "Overhead System C-K" which I believe is GM speak for the rear system, is 5 lbs 4oz.
There are 15.3 fluid ounces in a pound, with means the ORIGINAL R12 requirement is (76.5 + 4 oz) = 80.5 oz. My supplier (Mike) at Classic Auto Air says that R134a should be 70-80% of the original R12 charge. Which translates to: 56.35 - 64.4 oz or R13a for this unit, or 6 12oz cans. Mike said charging it should take a good 45 minutes. He mentioned adding 2lbs, then 1 oz at a time, watching the thermometers in the vents front and rear for "maximum chill". It's been in the mid 80s all week, and now it's 65 degrees out! Last run to the parts store to buy some "chilly juice" and IT'S ON! https://photos.smugmug.com/VehiclesO...IMG_9726-M.jpg |
Re: Suburban A/C fix + Vintage Air?
I've never had good results trying to extrapolate pounds of R12 to R134, HFC152, or R290/R600 blends.
I saved this method from some posts Jungle Eddy made about using hydrocarbon and other alternative refrigerants on a Fidonet Aircon message forum that I frequented on a dial in BBS system. Around 2001 or so. I thought it was older than that. This method always gives me decent results no matter what refrigerant is used. -------------- Posted by JungleEddy on September 05, 2001 at 08:17:44: via: or 66.25.151.188 More important stuff. How to charge an A/C system. Note: This method will work for any automobile A/C system regardless of refrigerant type. The pressures I list here will only be correct for HC’s. I have been trying for the past couple of weeks to come up with a “system” that would allow just about anyone to properly charge their A/C system. While this method I have developed is not fool-proof, it yields the closest thing to a perfect charge I have found. I have tested it on three “non A/C” mechanics in the past few days with great success. First: If you have not read my previous post on vacuum, flushing, oil supply, leaks and fans etc etc, please do so now. You still need a properly assembled system to get proper cooling! This ENTIRE process makes a few IMPORTANT assumptions!! 1. The ambient air is OVER about 84 degs. 2. You have a set of A/C gauges 3. You do not take shortcuts. 4. You are able to read and comprehend enginsh. This process will work down to about 80 degs ambient air, but will be MUCH MUCH easier to over charge below 85 degs ambient air!! Relative high side pressures will be lower at 80 degs ambient and pressure drop after wetting the condenser will be less dramatic. Pull a hard vacuum for a minimum of 15 minutes, 60 minutes is perfect. Static charge the system to about 65 psi while the engine is NOT running. If you have a low pressure cut out switch on your system you will need to adjust it down to 18-19 psi sometime during this process. Personally, I find it easiest to do this about midway (now) through the charging process. Remove the connector from the switch and turn the adjustor screw about 1 full turn counterclockwise from its factory position. (counterclockwise is less psi, clockwise is more psi, 99% of the time) Start the engine and turn on the A/C, recirc, max fan, and engine at idle. Max fan is important, since it will help keep the evaporator from freezing as you charge. Charge the system slowly (if you have to!) until the compressor stays on fairly continuously at IDLE. The adjustment I illustrated above should give you a cut out psi of 12-18 psi. Watch your low side gauge and SLOWLY increase engine rpm. The low side pressure will drop slowly but substantially because you are still undercharged. Watch it drop from 20+ psi down through the teens and carefully note where the compressor cuts out. Return the engine to idle and pull the connector to the cut out switch and adjust it accordingly. Try this several times until, as the engine is slowly revved the compressor cuts out at about 18-19 psi on the low side. The Charge: Bring the engine rpms up to a continuous 1200-1800 rpm. Begin to add refrigerant (if you have to) SLOWLY until you notice that the air at the vents is noticeably cooler than the ambient air, say at about 65-75 degs or so. At this point grab your garden hose and hose down the condenser; soak it once only. Your pressures will drop dramatically. The high side should drop below 150 and the low side should drop low enough to cycle the compressor, or if the switch is temporarily “jumped” the low side should be well below 20 psi. I prefer at this stage to jump the connector to the pressure switch to keep the compressor running continuously. It makes the process go much faster, but you risk freezing the evaporator. Now, watch the system pressures rise as the water evaporates and the heat in the system and stabilizes and equalizes. This can take a long time if you have a mechanical radiator fan. The point where the pressures remain relatively constant is called equalization. Here is the key: (After wetting the condenser) As you are watching the high side pressure rise from 160psi through (potentially) about 205psi the LOW side should REMAIN from 21-24 psi. If the high side never sees 145+psi you are still low on charge as long as the ambient is 85 degs or above. If as the high side needle swings through 160psi the low side is still below 20psi, you will add more refrigerant AFTER wetting the condenser again and dropping the pressures. Keep doing this until the low side remains at 21-24 psi while the high side swings through 160psi and finally settles at equalization (no more rise) Keep the engine rpms constant and wait for equalization (or close) each time before wetting and charging. If you are going carefully and slowly you could see a high side over 225 at equalization BEFORE you reach a full charge. The high side will DROP as you come closer to a full charge. Be aware that if you over-charge, the high side will climb again and never come down. Note: If the ambient air is above 95 degs, stop watching the low side after the high side climbs past 205 or so. Especially if you have weak fans. Note: Take your time and wait for equalization and water evaporation off the condenser before adding refrigerant. An overcharge can occur with no more than an extra 1.5 ounces of refrigerant!! You can double-check your work at any time (and I suggest doing so) by waiting for full equalization and stabilization of pressures. Then, carefully MIST water into the condenser SLOWLY SLOWLY dropping the system pressures and watching for the same readings on the gauges as listed above. When finished you should have a sweaty return line all the way back to the compressor. When the return line begins to feel chilled over the first portion of its length, you are approaching full charge. Do not forget to reconnect the low pressure cut out switch! Do not consider your vent temps accurate until the vehicle has been driven for about 10 minutes at moderate highway speeds!!!! Idle low side pressure should not exceed 40 psi (34-38 actual) if everything is working well; good fans etc…. The idea here is that the compressor should NOT cycle when ambient air temps are above 81-84 degs. Interesting note for tech heads: If you are charging SLOWLY. You will find at first that the high side will be at a higher pressure, after equalization, on a low charge than at a correct charge! Remember, raised heat = expansion and/or pressure. Why: (basically) Within a certain range, the pressure in the condenser (high side) is MUCH more affected/determined by the temperature of the refrigerant than its volume. ALL THINGS BEING EQUAL, the condenser has the ability to lower the temperature of the refrigerant passing through it “X” amount and no more. The compressor, in compressing the refrigerant, heats or raises the temperature of the refrigerant “Y” amount. Lets say the temperature of the refrigerant entering the compressor via the return line is “Z”. So the final temperature “T” of the refrigerant that gets to the orifice/exp valve is: Z+Y-X=T If we could lower the value of “T” the entire system would work more thermally efficiently and at lower pressures on the high side. So, ALL THINGS BEING EQUAL, you could 1. get a larger condenser and raise your “X” value or 2. lower the value “Z”. A full charge on an A/C system will not only have enough refrigerant in it to keep the evaporator “chilled”, but JUST ENOUGH that the line leaving the evaporator and returning to the compressor will also have substantially cooled refrigerant in it THUS LOWERING YOUR “Z” value!! Hello!! Note: Over charging will allow actual condensed refrigerant (liquid) to make it all the way back to the compressor. As we all know, you cannot compress a liquid…boom/screech. ---------------- |
Re: Suburban A/C fix + Vintage Air?
It kills me a little that Hatzie sent that message while I was charging the beast and did not see it until after!
Boys and girls, here's the report. 65 degrees ambient air temp. 3:45pm Front Vent temp: 82 Rear: 80 added one can of refrigerant (12oz). At some point during this HOUR I actually read the directions and shook the can, did the 12 to 3 tilt. This speeds things up. The fans kicked on when they should, the compressor kicked on, everything was looking good. No blown fuses or craziness. So far so good. https://photos.smugmug.com/VehiclesO...IMG_9731-M.jpg 4:32pm Front Vent temp: 88 Rear: 81 (we closed the windows!) Added second can. 11.9 oz 4:50pm Front Vent temp: 64 Rear: 68 Can no. 3 12.05 oz 5:38pm Front Vent temp: 50 Rear: 52 Now we are cooking with gas! As a test I put the thermometer in my CAR: 44 degrees coming out of the dash. This was now what I was shooting for. At this point I slowed down (It was already slow) and measured 1-2 oz at a time, waited 5-10 minutes and compared the vent temps. As soon as the temp started to stabilize (could not get it to drop further) I stopped. Temp from the dash was 48 degrees in the front and 49 rear. Should I be happy with those numbers? Figure out the way to measure these that makes sens for you! https://photos.smugmug.com/VehiclesO...IMG_9734-M.jpg Honey, Have you seen the kitchen scale? https://photos.smugmug.com/VehiclesO...IMG_9736-M.jpg This was the lowest temp I got out of the front. https://photos.smugmug.com/VehiclesO...IMG_9749-M.jpg |
Re: Suburban A/C fix + Vintage Air?
I am not a professional but I would be happy with that, especially for not pumping down the highway.
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Re: Suburban A/C fix + Vintage Air?
Also here were some pressure readings while running things at the end.
https://photos.smugmug.com/VehiclesO...IMG_9739-M.jpg |
Re: Suburban A/C fix + Vintage Air?
Finally got out to drive the Burban:
Just around the block, looking much better!: https://photos.smugmug.com/VehiclesO...IMG_9780-M.jpg Then to the parts store and a brief stint on the highway: https://photos.smugmug.com/VehiclesO...IMG_9788-M.jpg PARTY PEOPLE we have some REFRIGERATION! 36.5 Degrees indicated! I'm frankly shocked and amazed! https://photos.smugmug.com/VehiclesO...IMG_9781-M.jpg |
Re: Suburban A/C fix + Vintage Air?
Wow.....
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Re: Suburban A/C fix + Vintage Air?
I hope this thread encourages someone to go for it! A big thanks to everyone who pitched in and gave advice, or even just watched on this thread, it helped keep things rolling!
Meanwhile here is a quick summary of what it took to get cold air blowing out of the vents: First let me say I'm a hobby mechanic. The idea of adding AC to my rig was pretty ambitious if not crazy sounding, considering I knew NOTHING about how AC actually works. I only know a *little more now, but I get how it all goes together now. The real scary part was there are very few "real mechanics" that would tackle a job like this, so if I gave up along the way there was no "higher authority" I could petition to finish it. My theory is this: once you 'own' a vehicle of a certain age, you OWN the problems. Very few "professional mechanics" are REAL problem solvers. There is just no money in it. This makes me VERY grateful to this community, for the moral support and technical advice here. I committed to this project two years ago, and made some pretty good mistakes, which stalled me out considerably. I bought the wrong sized compressor (and bracket) which was not a trivial expense. Calling "Classic Auto Air" and talking to Mike Oliveras was the best thing I did on this project and he set me straight and helped me size the system and get the parts I needed. In the end I complete this job Here is a rough cost breakdown: Salvage Yard Rear AC Unit, dash switch (and hoses I ended up not using): $150 (I bought some other things so I think this is close) Classic Auto Air Compressor Bracket D-rings to mount hose High side, low side hose (35ft?) Parallel flow condenser Mounting brackets All AC line fittings $1,400 Things we forgot Trinary switch (summit racing): ~$50 Miscellaneous Wiring, relays, connectors, crimpers, etc Refrigerant Tools Gauge set & Vacuum pump: $140 ACCrimper: $140 Orifice tool: $15 refrigerant tap: $15 Thermometers: $20 Doing the job yourself and having it work: Priceless Things I would do differently Spend time exploring hard line options. I doing research it seems there are ways to make your own "braze on" hard line AC connectors. Also vintage air has a product called "u-bend-em" which is a hard line connector that seems like it would be great to get through the firewall. Do more research on charging the system for maximum cold. (turns out after my test run I was ok!) Other Options Classic Auto Air and Vintage Air both make "kits" where you can remove all the stock stuff and replace it with all brand new parts (front AC only) for something like $1500. Plug and play, and this is probably a great option. I don't think anyone makes a dual system kit, so you would still face some of the same challenges: What size compressor, how to run lines to the rear, and what rear unit will fit and not look terrible (why I went with stock). So of course the expense rarely makes sense considering you can buy a suburban for the cost of my AC System! ...THERE ARE MANY LIKE IT, BUT THIS ONE IS MINE. |
Re: Suburban A/C fix + Vintage Air?
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I went through the a/c when building my Dually. I did the parallel flow condenser to help w/the 134 refrigerant. New hoses. Then relied on local shop/dealership guys to get it leak tested & correctly charged. I've never got it to work correctly. It would blow cold (well, cool) sitting @ idle. As soon as you start driving? It shuts off. My guess is head pressure but I couldn't get anyone w/the equipment to keep @ it like what you went through. Congrats on a job well done. |
Re: Suburban A/C fix + Vintage Air?
I have cold a/c on my crewcab, but I put a 10" fan on the front of the condenser so it stays cold while sitting in traffic. gotta keep air moving across the front.
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https://www.oreillyauto.com/detail/b...+gauges&pos=19 |
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That would be admitting they screwed up and didn't clean the old oil out of the system thereby ovrefilling with oil. |
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Re: Suburban A/C fix + Vintage Air?
Congratulations! There may be others but I bet they are not 36 degrees inside! May you enjoy this AC for a long time sir!
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