Can I just rip out my AC System?

[1972BlueC20]

I got my truck all torn apart today. I was doing a heater core replacement. Got the heater box out and got the new heater core secured in place inside the box. I also went ahead and changed out the blower motor and metal fan blade. I'm also replacing the heater blower speed resistor while I'm inside there too. I also have all the gaskets for the heater box.

I was having some troubles with air coming into the vents when driving down the road and some of you guys suggested that the blend door was stuck open or in need of a gasket to seal it off when closed. I also was having trouble with my heater control levers. Seemed they were binding a bit and were hard to move from left to right. Well now that I got everything apart I see that the lever for the door in the floor box area was tweaked and bent causing it not to close all the way hence the air coming through the vents and the binding of the controls. I tweaked everything back and it's now working smoothly. With the heater control out of the dash the levers seem to move smoothly too and the cables are all going back and forth with the lever movement. So I guess if I hook everything back up correctly it will work properly now?? Is there anything else I should check or replace while I'm inside the dash?

So I think I have all that sorted out for the most part. I also noticed that my heater air ducts were all dry rotted and torn apart or had come off where they were supposed to be hooked to. So I'm ordering new ducts and will secure everything with hose clamps to the heater box inlets and the dash vents.

Any suggestions and or help is greatly appreciated!!!

My main reason for this long post is to ask you guys a question.

I have an old dealer installed Clardy hang on aftermarket AC System in my truck. It's never blown cold since I bought it and recently it stopped blowing all together. I found out today why it stopped blowing and that's because the fuse for the blower had blown out. There may be another issue that caused the fuse to blow, so I don't know if changing the fuse is a long term fix. When the AC was working, it never blew cold. I recently got a quote to convert it to R134a for $800, and that's without a new compressor!! I passed on that deal. My compressor is an old York compressor and its making some noise, so it probably needs replacing too.

My question is can I just unhook everything and just rip the AC system out? I think the system is pretty much empty anyways of freon. I know technically you're not supposed to just bust the hoses off, but if you don't tell I won't LOL.....is there anything to be mindful of if I do that??

I may eventually install a vintage air system later down the road or just go with no AC.


Oh and I forgot to mention too, nobody in my area will mess with R12 anymore. So unless I can do the work myself, converting to R134a is the only way if I want AC. My initial idea, before the blower stopped was to just fix any leaks and recharge with R12. Nobody around here that I KNOW OF will do that for me.


Here are some pics of what I'm dealing with :

[1972BlueC20]

a few more pics :

[wreckedchevy]

I ordered the plastic replacement ducts instead of the original style just cause I thought the would be more forgiving and age resistant but they don't fit worth a darn they are very loose and just fall off. I couldn't find a way to get hose clamps on them but used black zip ties and worked perfect. One more note if your defrost vents are the originals they break a lot easier than I thought both of mine completely exploded in my hands taking them out.

[57larry]

could junk it all and go with Vintage Air

[PanelDeland]

While you've got it apart, lube the cables well so that they continue to slide easily. I usually use a lock lube called "Lock Ease" but it's graphite and can get messy. I had my cables off when I did the heater core(non A/C) and left the cables laying in a drain pan of oil, then let them drain for a day before reinstalling.

[1972BlueC20]

Thanks guys!

I will lube the cables too, good idea!

So what will happen if I bust the hoses off the compressor? Is it a lot of pressure? Can it cause injury? That's really my main concern....once the pressure is released It's just a matter or pulling all the components out.

Also the A/C hoses go to a trans cooler looking thing in front of the radiator. Do I just remove that whole thing too?

I will need to plug the holes where the ac hoses go through the firewall near the heater box. Do they sell any pre-made rubber plugs? I can't seem to find them if so.

[see ten]

crack open a line... if there's any pressure on it... you'll hear it. Walk away... it'll gas out in a few minutes. Remove anything associated with that ac system and ditch it.

[Ozzy2013]

You can bleed off the system at the schrader valve thats where the fill is for the system.The conversion to r134 isnt hard at all just evacuate the system and refill with oil and coolant .I would replace the compressor you can buy used ones at the junk yard reasonable .Texas can get hot!

[1972BlueC20]

Sweet, so let's assume I wanted to replace the compressor and convert to R134a.

What tools would I need to flush and fill the system?

New hoses? Condenser? Compressor? Oil? Freon? Fittings?

I know really nothing about AC systems, but I've been told with my skill level I can do it.

[joey8383]

Be careful dumping any refrigerant. EPA fine is $$$$. And liquid refrigerant can cause severe burns.
That compressor will sell on EBAY. Back in my 4 wheel drive days, we would use them old York compressors for onboard air. They're tough

[Blown06]

Pull the plastic caps at the suction and or discharge of your compressor, they should just screw off. There should be a shraeder (sp?) valve eye hind them. Put on a pair of gloves and use a small screwdriver to relieve the system pressure. Just like letting air out of a tire. Then you should be all set for cutting the hoses.

The thing in the front is the condenser and can be removed. If you plan in the future to go with a vintage air or other system, all that stuff will get replaced anyway.

Hard for me to tell on your pics but you could also remove the belt to the compressor. If something else is also getting driven by the belt then just leave it on. The clutch will keep the compressor from engaging. Technically you shouldn't vent the system, but the law states that you have to recover a percentage of it. If there is zero pressure, it's hard to recover a percentage of zero. Wink wink!

[joey8383]

To convert, dump your old oil from compressor in to a measuring cup. Or dump it and look up the factory oil charge. Fill with proper amount of PAG oil. Leak check with dry nitrogen. Dump nitrogen out. Vacuum with a vacuum pump down to 500 microns. Weigh in charge of R134a (roughly 2 lbs +/- .75 lb?)
Need:
Gauges
vacuum pump
micron gauge (or chance it and just run the vac pump a couple hours to be sure)
refrigerant and oil.

R134a condensers are usually larger than R12 condensers. I have converted a bazillion R12 cars and some will run higher than normal head pressure due to fact that the condensers are smaller. You could replace the condenser or make sure fan or electric fan is moving plenty plenty plenty of air. Especially at idle. Good luck

[57taskforce]

I've converted a few r-12 systems over. It's just a couple 134a fittings, vacuum, oil charge,134a charge, cold air. Be advised it won't run as efficiently(ie won't be as cold) as it would be with r12. It will keep you cool enough tho. For the vacuum and recharge any shop should be able to that for you for FAR less than 800. No sure what the $800 quote entailed but seems very steep to me.(for a few hundred more you could get vintage air)

[no1udknow]

Ummm, quick tip about refrigerant. If you decide to "crack open a line" or "bleed it out at the shrader valve" ease do it ouside and not in your shop. First off, it is a huge fine if someone sees you doing it, but from a safety standpoint, r12 and r134 displace oxygen. Every single molecule of refrigerant gathers 10 molecules of oxygen to it and becomes heavy and falls to the ground. This in turn displaces a significant amount of oxygen and can cause you to pass out if it is not in an open ventilated area. Safety first that's all I'm saying.

[no1udknow]

Originally Posted by 57taskforce

I've converted a few r-12 systems over. It's just a couple 134a fittings, vacuum, oil charge,134a charge, cold air. Be advised it won't run as efficiently(ie won't be as cold) as it would be with r12. It will keep you cool enough tho. For the vacuum and recharge any shop should be able to that for you for FAR less than 800. No sure what the $800 quote entailed but seems very steep to me.(for a few hundred more you could get vintage air)

I always hear people say that r134 is not as efficient as r12, do you think that possibly there is a need for a greater restriction/orifice before the condenser? I used to do some home A/C retro fits and I know if wevever swapped for 134a we had to change the orifice at the condensor. It looked like a tiny brass carburetor jet.

[Katrina/10]

That old AC system you have looks good, I'd try to fix it. May just need a charge, in Texas I'm sure you will want some cool air in the summer.

[engineer_gregh]

I have the exact same set up on my 71. Installed by a dealer in Birmingham AL in 1979 at a cost of $440. I've removed mine to replace all the rotten hoses and get new condenser. I'm also looking to go with crimped hose connections as I'm not sure the barbed connections will hold up to the increased pressure of the R134a. Mine worked ok till one of the lines split under pressure last year.

[1972BlueC20]

You just brought up a good point. I think I'm going to try and keep the hang on AC system, but I want to replace the dryer and the hoses with the new crimped style hoses and convert to R134a.

How and where do I get the right length hoses with the newer crimped style ends like the newer cars?

[engineer_gregh]

I'm still researching that myself. I'm going to mock it up with heater hoses (cheap to do) to get the right length then try some local shops that do hydraulic hoses. I like the look of the hang down air and I don't want to give up my glove box with the vintage air kit.

[57taskforce]

Parker supplies the hoses for vintage air, (or at least that's what came in the kit for my 57) they are quality crimp fittings and quality hoses as far as I can tell) I'm pretty sure any local hydraulic or even residential ac companies can get ahold of what you need

[1972BlueC20]

Cool, if you figure anything out please let me know and I'll do the same.

I might just hook everything back up and see if the system will hold a vacuum for now. If it does, then i might just retro fit to r134a and see if it all holds and works with the existing hoses. I'm watching videos now on AC work. LOL. Gotta love YouTube!!!

I just gotta figure out the procedure for flushing the system and getting the new oils inside.

I've learned now how to check for leaks, how to put a vacuum on the system and how to charge.

I'll need to go buy a vacuum pump, a gauge set to start. Making a list of what all I will need.

Any comments or additions would be greatly appreciated.

[no1udknow]

For the price of vacuum pump, gauges and fittings, you might be better taking it to someone or maybe finding a mobile guy. I know here in Cali there are guys that will come out just to recover the refrigrant. They could probably vacuum test it also.

[joey8383]

Using a vacuum as a leak test is a bad idea. A perfect vacuum of 30"H.G. is equivalent to a positive pressure of about 8psig. If you have a system that won't hold 8psi for a few minutes, you've got a huge leak. Also, any moisture in the system will cause the vacuum to rise.
Do the oil change. Do not mess with the restrictor orifice. Your old set up probably even has a TXV (thermal expansion valve) on it instead of an orifice. A TXV will modulate the flow of refrigerant in to the evap based on superheat and keep the liquid level perfect in the evap. Replace the hoses. Pressure it up to about 150psig with 134a and go around all your connection with soap bubbles. Dump the charge, vacuum, weigh in the charge using a postage scale or similar.
I just seen a 30lb drum of 134a at an Atwood's store (farm store) for $89. I've seen the same deals from parts stores around here.
Once you get the charge weighed in, Let the truck idle with AC on high. If the high side pressure converted to temp is 35 degrees or more than the outdoor temp, you should add an electric fan or make some kind of improvement on airflow across the condenser. Again, the old R12 condensers are small compared to the R134a condensers. I think that's why people are saying R134a doesn't cool as well. In fact, R134a has more BTU carrying capacity per pound than R12.

[1972BlueC20]

Thanks for the info joey, can you walk me through basically what i need to do in this case :

I will just put everything back together on my ac system (I haven't busted any hoses off, so if there was any Freon in the system then it's still there). Last time everything was working, the compressor was kicking on and off, but it was only blowing room temperature. Assuming it's still the same after getting everything back together, can you give me a step by step of what to do?

I need to see if there are any leaks, then I need to evacuate and recharge with R134 after changing some parts (can you tell me exactly which parts to change?)


Thanks in advance, I'm learning from you guys

[1972BlueC20]

Also separately, what if I was able to get my hands on some R12?

Could I dump what's in my system out, then put a vacuum on it then charge with r12?

I mean if my ac system is not blowing cold, does that mean for sure that i have a leak?

Sorry if this sounds stupid, I'm learning about AC.