Air conditioning Reinstalling

[1979C20]

I wish to know what it would take to put AC back in my truck. I'm not worried about updating to R134a, I'll keep the R12, as I'm just trying to make it easier to get through the AZ summer. My compressor clutch was seized. I still have the brackets, And all of the other parts are still hooked up. Can somebody Identify each part and tell me which would need replaced or serviced after being left open for a year? I hear there is a part the will dry out after 3 days or so of being open and will need to be replaced. Should I look for a compressor on craigslist? Could I just replace the clutch? Thank you in advance. The truck is in my Signature. And the compressor is like this http://www.oreillyauto.com/site/c/detail/MUR0/58094.oap?ck=Search_a!s!c+compressor_1032196_2896&keyword=a!s!c+compressor. I found a compressor never before installed for 80 on craigslist.

[Irish_Alley]

On my 94 back in like 03 my wife rear ended some kid at school that had to stop in the middle of the road because some other dumb kid from school who thought it would be funny to slam on their brakes for no reason just to make everyone else behind slam on their brakes. Then he tells the cops I had on my turn signal and was turning but for some reason the cop let him go even though he passed the only right turn on the road by 20 feet before the collision lol anyway. it was left open since then and had a old r12 condensers put on "the ac's radiator", well I had to get a new one of those anyway but I ended up replacing that the compressor the accumulator and the orifice tube. The accumulator will suck up moister and render in-op that’s the part your talking about it won’t dry out but the opposite. Also about r12 you can’t touch it unless you have some saved up in a bomb shelter lol convert to 134a so you can do it your self. I would replace the whole compressor if you have the extra money 80 bucks is abou tthe price of just a new clutch so i would go for that one on c list, also flush the system with ac flush and then dry it out with compressed air once you set it all back up you have to rent or buy a vacuum pump from someplace I put I think 100 or 200 down on one from AutoZone and got that back once I returned it. But a small detail they don’t tell you are you needing hoses to set it up they don’t come with the pump and get a Manifold pressure gauge. Vile can help out a lot more than what I have but that should get you started

[1979C20]

So, if i were to get that compressor, i would need an orifice tube and an accumulator? What would it take to convert to r134a? And what about the drier? I heard something goes wrong with it when left open.

[Irish_Alley]

the dryer is the accumulator it has something in it like what you find in a shoe box that says dont eat if a system is left open it will suck out the moister in the air and render it no good due to moister in the ac lines will cause problems that why you need to vacuum it out first. the orifice tube has a screen type of filter it will get dirty very easy remove it, flush the system and replace it. the conversion kit is only different fittings(srader valve) for the high and low side. most gauges you buy only work with 134a the r12 srader valve is bigger is size and wont fit in the gauge

[Blazin]

Never flush an AC system out with compressed air, it contains moisture.
There is a chemical cleaner for this. Smells allot like brake clean. Then you flush that out with nitrogen. The descant is replaceable if accumulator is serviceable. if not you will need to replace the whole unit. You also don't want to flush the new pump. When installing the new pump you should dump a small amount of Pag oil or equivalent into it before hooking up the hoses. My opinion you should do all the mechanical replacement / assembly, then take it to a shop that has an AC machine. Have it evacuated, vacuumed, and leak tested. If its tight they can refill it with 134.

[Irish_Alley]

lol sorry about the compressed air. we used the a/c flush then compressed air then vacuumed out the system. also we didn’t run the flush threw the compressor or accumulator. But we did threw the hoses, evaporator core (in the firewall) and condenser

[1979C20]

So, to make a list, to put the ac system back in working order i would need
compressor
orifice tube
flush, vacuum, fill of refrigerant

To convert to r134
use the same compressor,
r134 accumulator(drier)
lines for the accumulator

Or do i need the smaller compressor that i believe is deisgned for r134?

[Irish_Alley]

Compressor
Orifice tube
Accumulator

Now when you flush you don’t need to flush the new parts just flush the old then clean it out somehow i did mine with compressed air and its still working over a year ago. But if you want to be safe use nitrogen then vacuum out the system (this removes moister from the system. it causes the moister to boil and then the vacuum does that sucks it out)
Get a r12 compressor i don’t think r12 and 134a parts are interchangeable. the conversion kit just comes with new srader valves its only two valves high and low i think on r12 the high and low are both big and the same size while on the 134 the low is smaller than the high so you don’t plug into the high side and blow the Freon can up in your face

[1979C20]

Quick update, im buying an A6 compressor tonight off craigslist for 90. The guy bought it, found out it was the wrong one(needed an r4) and couldnt return or swap it out. Its brand new in the box. So, im going to buy the dryer, fittings, orifice tube, and orings soon. I know I.need the system vacuumed, but I need to know a few things. What oil do I need for it? How much oil? How much r134-a refrigarent for the system? And how do I fill the compressor with oil. My friends dad owns a shop so im going to take it to him for the vacuuming. Thanks in advance!

[1979C20]

Also, I need some wiring tips. I believe I have a blue wire and a green wire on a clip and a black wire with a terminal lug on it. Those are the correct wires for the ac, correct? And how could I check them for functionality?

[1979C20]

Here is my current drier and its shrader valve

Here is the shrader valve on one of the lines

And here are the caps for those valves. the one on the left is for the valve on the line and the other is the valve on the dryer

Any Idea which line is the high and which is the low?

I bought that Compressor last night.



Here are the papers included in the box.




What is the Superheat switch and the High side pressure switch and where can they be found. It says I'll have one or the other on the old compressor. It also says its pre-filled with 10 FL. OZ of oil. And it specifies that I'm required to buy a new Orifice tube, and Dryer. I talked to my buddies dad and he doesnt have an evac for r12. So I'll have to find somewhere who can flush the R12, vac, and fill it with R134. I still need to buy the dryer, orifice tube, and the fittings. I can probably just pay the shop for the refrigerant. How much refrigerant is required for the system?

[Dr_Snooz]

Use Ester oil or double-end capped PAG oil. Don't know how much though.

[1979C20]

Use Ester oil or double-end capped PAG oil. Don't know how much though.

turns out the compressor was prefilled with double end capped PAG oil.

[1979C20]

Well, I installed the compressor on the truck tonight. I tried removing the orifice tube and it wouldnt budge, and ended up breaking halfway up. I tried threading a pointed bolt into the center and it ended up getting pushed to the side and pierced a hole in the line on the bottom of the evap core. So, now I have 3 options. Weld it. Replace the core. Or cut the pipe before the hole, put the nut on it, flare it, and buy an extension piece that can thread to the end so I can put the orifice tube in it, then attach my rubber line to the new extenaion piece. Ill probably take option number 3. I bought flush solvent, the dryer, orifice tube, orings, and crush washers. Tomorrow I will flush the lines, the accumulator, and thn probably the evap core. Ill post some pics of the damage tomorrow. After I get it sealed up ill take it to my friends dads shop and heck draw a vacuum on it and orobably fill it for me. My blower moter relay burnt out some time before I got my truck, so I ran a toggled 12v wire to the motor power wire so I could have my heater during the winter. Im assuming ill need a new relay for my ac to work? Because I hooked up the 2 wires and grounded the one with the terminal lug on it and when I moved my selector switches the clutch didnt engage. And the fuse is good.

[Jason S]

The clutch on your compressor won't engage unless the Evaporator Pressure Control switch senses pressure in the system (i.e., charged system).  That switch is found on the accumulator with two green wires running to it. 

To see if the compressor clutch engages: make sure the compressor wiring is hooked up and grounded, turn the ignition key to run, switch the control panel to A/C and then jumper across the wiring plug that goes to the pressure control switch. The clutch should click.  If not, there is a break in the wiring or a defective switch in the dash control panel.  I'm looking at a 1979 Chevrolet Light Duty Truck service manual and the only relay that the A/C system has is the blower relay. 

The auto parts stores sell the R12 to R134 adapter fittings for the charge ports. They're aluminum and just screw onto the R12 charge port fittings. Be sure to check/replace the shrader valves in your R12 ports.

The original R12 system called for 3 lbs of refrigerant.  What I have been told is to use about 80% of the R12 capacity, and have found that about 2 1/2 12oz. cans cool the truck pretty well.