AC Guru's! Need HELP!!!!!!!

[BlackBetty]

Here’s the situation.  1981 Chevy K10 with what appears to be a dealer installed ac system.  When I got the truck the ac didn’t work (no compressor), but the heater kind of worked, meaning it pushed a little air through the vent VERY slowly.  The back side of the dash control switch was broken so none of the slide levers worked properly, so I can’t say if there is a blower problem or not, but I am assuming there is so it will be replaced.  Eventually the heater core died and dumped coolant on the floor of my cab.  Now I would like to get the AC back up and running but I’m a total retard when it comes to the AC system and I can’t seem to find my same set up on the web or junk yards to help me piece this thing back together.  Here are some pics to show what I have.  Take a look at where all the lines go through the firewall.  This truck originally had the 4.1L straight six and manual tranny (SM465).  Before anyone asks, both are already gone so I don’t have them.  I am putting in a 350 and a 700r4 and a larger radiator (from the 454).  The AC condenser is currently located in front of the radiator. Don’t know if it’s good or not, again assuming it isn’t.  Haven’t even dug for the evaporator yet, based on where the drain line is, I assume it’s in the box in the cab behind the glove box with the heater core, but that’s a guess.

Random parts I have laying around:
1.   universal accumulator tank
2.   new dash control unit (which is not the same as what is in the truck now on the face, but the back matches up so I think it will work)

http://i1161.photobucket.com/albums/q509/graydog39/ac.jpg
Passenger side blower assembly / heater core lines
http://i1161.photobucket.com/albums/q509/graydog39/ac2.jpg
?Liquid and drier? Lines to left of brake booster

So, the question is, will I be able to use the lines as they are now?  I am concerned about the location through the fire wall. 
Can you trade out the ends of the lines to fit the newer R6? (pancake) type compressor.  I wanted to go with the R134 set up for servicing convenience.
Most importantly, what do I need to replace when making the switch to 134?

[Captkaos]

Take a picture of the inside of the truck.
I would probably opt for a factory donor or spring for a Vintage Air setup before trying to find parts for this...

[BlackBetty]

Do you mean a picture back behind the glove box in the dash?

[Captkaos]

both if you can.

[VileZambonie]

I agree, either find a factory donor or go with a new aftermarket kit.

[zieg85]

Does the slider look like this...

[Jason S]

I've done the A/C setup in an non-A/C truck using an aftermarket kit (similar to yours) as well as installing a factory A/C system. I've also had an aftermarket A/C setup that I removed to install a factory A/C system.

Overall, it takes a little bit of time to completely remove a factory A/C setup and install into a non-A/C cab, the final results are well worth it. In my experience the factory A/C setup has simply outperformed the aftermarket type.

You can use R-134A in any system. You really need to make sure that you have the system clean and evacuated thoroughly to get the best cooling. This means clean lines, clean condenser, clean evaporator, new accumulator/drier and a clean compressor with new, clean, R-134A compatible oil.

The condenser is supposed to be in front of the radiator as that is where you'll find the coolest incoming air needed to condense the refrigerant to provide for proper cooling.

You can purchase the individual fittings for the lines to connect to pretty much any A/C compressor.  You'll likely have to search the parts book at your local auto parts store and point out which fitting you need. 

If you're wanting to refurbish the aftermarket A/C system, it would be a good time to go ahead and replace the A/C hoses. You'll probably have to remove the evaporator from within the dash to remove the hoses from the evaporator. 

Most of the systems that I've messed with have the evaporator situated above the heater box within the dash assembly. To remove the evaporator requires pulling the dash pad off, removing the glove box, unbolting the metal dash panel from the cab and pulling evaporator  unit out from the dash.

There is quite a bit more that could be said about repairing the setup you have... My vote is to go with a factory setup.

[BlackBetty]

zieg85 - yep, that's the one.  It hit me that the ac wasn't from the factory when I got the new one.  This is the replacement that I ordered..

http://i1161.photobucket.com/albums/q509/graydog39/newcontrol.jpg

Thanks everyone for the replies.  I couldn't get anymore pictures, the guy had his gate all locked up by the time I got off work.  I hate flying blind into stuff.  The guy that is dropping in the motor and trans for me recommeded finding a donor and gutting out the whole factory system.  He of course offered to do it for me for $2k. Yikes! Just didn't know if he was blowing smoke or he actually knew what he was talking about.  He works on quite a few square bodies (has two others in his shop now).  It appears everyone agrees.
 
Jason S - It kinda surprised me that you found the factory stuff out performing the aftermarket kits, considering its a 30 yr old design and the aftermarket kits presumably aren't.  But I'll take ya'lls advice.

Any way I go I know it's going to cost me.  Guess I can't get my mind around spending a ton of time scrounging up and pulling a bunch of old parts that may not work.  Just need to focus on the fact I'm getting the right components/set up for my truck and repair/replace as it happens.  I'm in Houston and its always hot here, so I REALLY want to do it right.  I don't enjoy getting out of the truck soaking wet, but the fogging windshield in the morning and in the winter time makes driving it a little bit of a pain and a LOT dangerous!

Thanks again for all the help.  I've really enjoyed reading all the advice on this site (before I joined).  Glad to know you are willing to help out another newb.

[Jason S]

You definitely need good A/C in Houston...

My '73 GMC did not have factory A/C.  Shortly after I bought it, I put in an aftermarket type A/C setup from Old Air Products in Fort Worth.  I used a Sanden type compressor and an aftermarket compressor bracket. The A/C system worked well.  After about 5 years, the compressor locked up, so I decided to replace the system with a factory system from a '75 Chevy truck.   

As far as the aftermarket A/C I had, around Stephenville it would have trouble on really humid days; it liked to freeze up.  When I'd go down to College Station, it'd be worse. After I installed the factory A/C system, I never had any problems with freeze up.  Additionally, the volume of air the factory system A/C would push through the vents is greater than the aftermarket type.

This last summer, I drove the truck pretty much every day. We had over 100 days of 100 degree temperatures here in SW Oklahoma and I stayed nice and cool the whole time. 

I don't know if any of the other aftermarket systems are any better or worse than a factory system, but in my case the factory system just worked better.

[Captkaos]

GM put a lot of engineering hours in making the AC specifically for these trucks.  It doesn't surprise me at all..

[PO_BIRD]

DO YOU STILL HAVE THE DRIER ON THE TRUCK.