Factory A/C, what to do

[dmjlambert]

Folks, assume I know very little about A/C. I am able to understand mechanical things but an A/C novice and I have no tools related to A/C. What I have here is a 1969 CST/10 with A/C, and so far I have not done anything with the A/C. When I pulled the engine and fixed it up, I just unbolted the compressor and set it aside and left the hoses attached. The whole A/C system looks pretty much undisturbed although dirty, and the only things I see obviously wrong are the control panel has broken levers and the A/C clutch wire is chewed up, and the inside duct work has been re-routed in weird ways to accommodate a larger than stock radio.

So, here are my questions: Should I keep the hoses attached and fix and clean around the system assuming it is still pressurized? If I can get the controls, wiring, and blower motor and other such things working, I would then have the R-12 topped off and install a belt on the compressor and see what I get when I start it up. Would that be worth the trouble, or should I go ahead and completely disassemble right from the start?

[B. W.]

The system has probably leaked down over the years but, maybe not. If you have access to a set of gauges you can check for pressure. If you are going to do the work yourself you need a set of gauges anyway. Static pressure on a fully charged system should be around 80-100 psi. (someone here may have a more exact #) If it's low or at zero then go ahead & disassemble. If it's at, or close to full charge then leave it together & try it.

[engineer_gregh]

I just went through this with my truck. I did a lot of research before I started. Just a few things to consider; wear safety glasses as a shot of freon in the eyes can blind you, never open the high side gauge while recharging as the pressure from the compressor will feed back through the small can you're holding in your hand (dangerous), understand the difference in low pressure side and high pressure side, and its illegal to purge freon into the open air. Gauges are a must, you can get them from AutoZone as a loaner tool. YouTube has several videos on servicing A/C I found useful. There are lots of threads on this board to help in your decision to keep original or replace with Vintage Air.

[Luvinit]

Press in on one of the Schrader valves with a screw driver and you'll be able to tell if it still has any pressure. Then turn the front hub of the compressor by hand to see if it still turns this hub is connected to the pistons. More importantly figure out how the wiring functions and get the controls and cables working. An a/C mechanic can test and recharge the system. Good luck.

[davepl]

Presuming it's discharged and you want to get it ready for charging:

If you're going to do it yourself, you'll need the following:

Some kind of vacuum pump:
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

Manifold Gauge Set:
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

Then you get the system all set up, hook up the manifold gauges, run the vacuum pump to pull a full vacuum on the system, and see if it'll hold it overnight. If it does, then you go somewhere and get it charged up.

If not, you find and fix the leak, and repeat the process until it holds a vacuum overnight.

Since you'll have about $200 in tools to get that far, sometimes it's false economy doing it yourself and you should just take it somewhere that services AC. I wound up doing both, as my compressor leaked out the first fill I had... it only held vacuum for about 6 hours, which I convinced myself was "adequate", but it wasn't.

[SJLenz1340]

If your system is flat, then looking for leaks with a dry gas (nitrogen) under pressure is the best method. Do not use compressed air as the moisture level will cause you great pain. Leaks occur at all the usual places, compressor shaft, mechanical connections, and especially the evaporator since this is where dramatic changes in temperature occur. Get the system tight before evacuating or charging and you will be a happy camper.

[kaycee]

I did the same as you, I replaced all the vent tubes and such back to stock inside cab, traced all wires and hoses, brackets and got them hooked up and looking good for my taste. My compressor was good ,new drier and O-rings a 12 pack of bud light and off to my buddy's to recharge been holding good for a couple months now. He knew what oils and such to do so I'm not going to ask I am going to take him another 12 pack this afternoon .He did put 134 in though. I do live in Wyoming so the week we get into the 90/100 will be nice to have

[dmjlambert]

Thanks very much for all the information folks. This is the sort of thing I was hoping for in this post. If you vacuum and it leaks, how do you find the leak? Do you pressurize with air using some sort of pump?
EDIT I was writing while SJLenz1340 was writing. So where do you get nitrogen and is a pump required for that?

[Steeveedee]

Originally Posted by dmjlambert

Thanks very much for all the information folks. This is the sort of thing I was hoping for in this post. If you vacuum and it leaks, how do you find the leak? Do you pressurize with air using some sort of pump?
EDIT I was writing while SJLenz1340 was writing. So where do you get nitrogen and is a pump required for that?

You can get nitrogen from a welding supply, but you'll have to pay for the tank, since you don't have one. If you decide to do that, you can get a leak dye detector from an auto parts store. Just put some in - if you already evacuated it, then just take out the high side Schraeder valve and drip in the recommended amount. You could use oxygen, if you have that. The big deal is that you don't vent refrigerant into the air. Big trouble, if you get caught. BTW, the high side Schraeder valve is in the small AC line between the compressor and the condenser.

You won't need a pump, but you will need a regulator to reduce the pressure from the tank. You will then need an ultraviolet light to find where the leak is. #1 leak is from the front seal of the compressor. If you see an oil streak running across the underside of the hood, in line with your AC compressor clutch, it's the culprit.

[Already Gone]

Or, you can take it to a professional A/C shop and let them deal with it. Then you can enjoy nice A/C throughout the hot summer. I've done a lot of things to my trucks over the years and was reluctant to try them and oh so pround of myself after I did them and everything worked as it should. My feelings are there are lots of things we can do to our trucks but I like to leave what I call "specialty " work like trans rebuilds, engine overhauls and rear end and A/C work to the pros.

[dmjlambert]

Originally Posted by Already Gone

Or, you can take it to a professional A/C shop and let them deal with it. Then you can enjoy nice A/C throughout the hot summer. I've done a lot of things to my trucks over the years and was reluctant to try them and oh so pround of myself after I did them and everything worked as it should. My feelings are there are lots of things we can do to our trucks but I like to leave what I call "specialty " work like trans rebuilds, engine overhauls and rear end and A/C work to the pros.

Yes, I did exactly that with some things on the truck so far, such as my transmission and engine rebuilds. I will probably do some of the A/C dirty work such as cleaning, wiring, vacuum tubing, getting various bad parts replaced that are related to routing and blowing air, and the control panel, etc. Then for the closed refrigerant system, have a pro or a friend who is comfortable with it do that part.

[dmjlambert]

Originally Posted by Steeveedee

You can get nitrogen from a welding supply, but you'll have to pay for the tank, since you don't have one. If you decide to do that, you can get a leak dye detector from an auto parts store. Just put some in - if you already evacuated it, then just take out the high side Schraeder valve and drip in the recommended amount.

Thanks. I know somebody who does shade-tree mechanics for my newer vehicles, and he found and fixed some leaks on my Mazda Tribute using leak detector and ultraviolet light. He showed me some stuff. I think I will get him to help me with this.

[clay68c10]

Since you're wanting it to work correctly, go thru all the under dash stuff and fix/rebuild as necessary. It all gets worn out and it will work way better if you have all the ducting right.
I had a factory a/c truck when I lived in DFW and it was night and day after I repaired all the ducting. It's not too complicated or expensive.

[hdff]

There's a guy near you in ft. Worth that refurbishes and knows about old ac's. he refurbed mine and it looks great and has some great info. He goes by F A A Benny here on the forum and on Facebook..... look him up!

[dmjlambert]

That is a beautiful engine compartment. Did you leave it to him from beginning to end, drop off your truck and pick it up later with working A/C, or did you do some of the work yourself?

[Steeveedee]

Originally Posted by dmjlambert

Thanks. I know somebody who does shade-tree mechanics for my newer vehicles, and he found and fixed some leaks on my Mazda Tribute using leak detector and ultraviolet light. He showed me some stuff. I think I will get him to help me with this.

That would be better than dropping a pile of cash on the tank, regulator, etc. I only posted so that you would have an idea of what to do. It gets expensive fast. I have gauges and a vacuum pump because I bought an AC service machine from the shop I used to work at when the owner died.

[Steeveedee]

Originally Posted by hdff

There's a guy near you in ft. Worth that refurbishes and knows about old ac's. he refurbed mine and it looks great and has some great info. He goes by F A A Benny here on the forum and on Facebook..... look him up!

The under hood of my truck looks a mess, and I just don't really see why. I'm going to have to print this picture and do a "what is wrong with this picture" check on mine. Yours is a thing of real beauty! Of course, it's going to have to wait awhile. I had surgery on my left wrist (carpal tunnel) and it's hot enough to fry eggs on the sidewalk here in SoCal. It only got to 100 here today. I used to work in this heat, on cars and trucks. Those days are gone.

[volksworld]

a vacuum pump is also available from autozone as a loaner

[jeffahart]

Originally Posted by hdff

There's a guy near you in ft. Worth that refurbishes and knows about old ac's. he refurbed mine and it looks great and has some great info. He goes by F A A Benny here on the forum and on Facebook..... look him up!

Hey, how is your compressor wired? I noticed the two prongs are not connected.

[hdff]

Originally Posted by dmjlambert

That is a beautiful engine compartment. Did you leave it to him from beginning to end, drop off your truck and pick it up later with working A/C, or did you do some of the work yourself?

Thanks... I pulled the the evaporator/fan piece and the heater box and sent them to benny to be refurbished and checked because I live outside of Houston 4 hours from fort worth. He refurbed the boxes , checked and replaced the fan and evaporator, checked the expansion valve and poa, and knew of a place that could recore my original heater core. I installed it all including new hoses, condenser and rebuilt compressor. his work look great! everything went back together and looks great but I think the rebuilt compressor isn't working right so I need to check it out.

[hdff]

Originally Posted by jeffahart

Hey, how is your compressor wired? I noticed the two prongs are not connected.

that pic was from when I got it all together but had not squirted the R12 in it yet so I had the compressor unplugged to prevent a ut-oh. heres another one during install to check the wire length

[jeffahart]

Originally Posted by hdff

that pic was from when I got it all together but had not squirted the R12 in it yet so I had the compressor unplugged to prevent a ut-oh. heres another one during install to check the wire length

Got ya. Hey, I don't think your compressor is bad. If you have not charged it yet. When you start charging and adding refrigerant, it will cycle once it gets enough refrigerant in there. Just make sure you got oil in there, if not, then you will fry the compressor.

Nice engine bay. Mine is uglier than me....

[hdff]

Originally Posted by jeffahart

Got ya. Hey, I don't think your compressor is bad. If you have not charged it yet. When you start charging and adding refrigerant, it will cycle once it gets enough refrigerant in there. Just make sure you got oil in there, if not, then you will fry the compressor.

Nice engine bay. Mine is uglier than me....

I added oil and Freon and it was only cooling down to ~55*, not nearly cold enough to make a difference in the 100*/ 95% humidity here on the gulf coast of texas. now the compressor is acting like it locks up and won't turn sometimes .......

[jeffahart]

Originally Posted by hdff

I added oil and Freon and it was only cooling down to ~55*, not nearly cold enough to make a difference in the 100*/ 95% humidity here on the gulf coast of texas. now the compressor is acting like it locks up and won't turn sometimes .......

Ya, after all that effort you want cold, especially if you used the r12. A loose belt will make you think the pulley is locking up, but it's the belt not gripping. Tighten the belt. I would seriously consider getting an evacuation and charge from a pro. I do my own, but I can hang with 50s, our heat here is pretty dry. Anything under 90 and I'm happy to just roll down the windows anyway. I am considering a proper oiling and evacuation from a good shop. I just replaced my compressor(and nothing else) with a dirt cheep A6 and did my own hokey evacuation and roughly speaking oiling, then charged with cheap wally world 134a (not sure if there is a quality difference in brands)... and I am getting low 50s at the vent. So, you should be able to do better for sure.

[leddzepp]

The a6 compressor does not cycle, it's either on or off.

The a6 will "lock up" and act like it's hard to turn, and your belt will squeal like a pig.

I went through 4 of them over the years on various trucks before I concluded I was wasting my time and went with a new aluminum a-10. No more belt squeals, no leaks, no problems. A rebuilt a-6 will fail, it's only a matter of time. They also leak at the front seal. I will never use one again unless it's the original one on the truck from the 70's and still functioning.

I restored the factory AC in my 68 a few weeks ago, a-10 compressor and r-12. 36 degree air idling at a stop light in 100 degree heat without missing a beat.