AC Swap over

[usar17]

So i'm seeing a lot of AC posting this summer lol My 85 currently has a half-ass homemade AC system in it that the PO did. Everything in the cab looks stock, but under the hood you can tell that nothing is anywhere near original. Some of the hoses are starting to dry rot. BTW the hoses are just clamped on to the fittings at the compressor lol. AC Blower motor is separate from the heater blower. They butchered the glove box to add the second blower.

I currently get pretty good AC. But I know someday this system is gonna blow and **** on me.

I recently acquired a 1987 C20 that is just cab and motor now lol. Where i scored my newly rebuilt 350 TBI This truck also has factory AC in it.

How much of a head ache would it be to swap over the 87's AC and Heat System to my 85? electrical work and the Firewall are my biggest concern. Id prefer to have a factory system that I can easily repair compared to the butcher job I have now.

I would retain the current monster compressor instead of the pancake the new 350 has.

 

[Guardian]

The electrical really isn't that bad to do. I would consider moving the front clip and bed, might be faster.

 

[oneluckypops]

I just installed my A/c in my 85 NON A/C cab, honestly it wzsnt that difficult at all, the electrical and vaccume lines will all unplug from the donor truck and right back into your truck. the biggest trick is relocating the hole through the firewall, which really wasnt that hard at all. I would reccomend to wrap all your duct connections with a weatherstrip seam tape from a local lumber yard.

 

[usar17]

By duct connections are u referring to where the duct work meets the vents and at the manifold? I have never vehicle AC before.

 

[oneluckypops]

By duct connections are u referring to where the duct work meets the vents and at the manifold? I have never vehicle AC before.

all your vents are hooked into ducting behind the dash, which all connects to the heater box. In all theres about 5 pieces of ducting that has foam tape around where it connects to the trunkline which doesnt seal very well at all, If you wrap the connections with the weatherstrip seem tape. Some place on here this is a few pictures of all the duct work so you can see it clearer.

 

[HotRodPC]

Awesome, I see Pops already got in here cuz I knew he just did it.
I'd say you'll have it easy since you have a whole donor truck.
I've uninstalled one to scrap a truck and it didn't see to be to hard. My biggest suggestion, if it hasn't been siad yet, is to get a digital camera and start taking pics of under the dash as you are pulling it apart, so you have a guide as to putting it back if you get stuck, hung up, or forget how a piece went in. Be Cool !!!

 

[89Suburban]

all your vents are hooked into ducting behind the dash, which all connects to the heater box. In all theres about 5 pieces of ducting that has foam tape around where it connects to the trunkline which doesnt seal very well at all, If you wrap the connections with the weatherstrip seem tape. Some place on here this is a few pictures of all the duct work so you can see it clearer.

Very important, there is a lot of gaps on those connections that I found on mine. Especially the heater box to the defrost box, I have a huge gap on mine. Here is some pics and info:

http://www.gmsquarebody.com/forum/showthread.php?t=1559&highlight=removal

You must be registered for see images attach

I thought OLP had a thread with pics too but I can't find it, or somebody else had it too, they were doing this and posted pics.

Here is another one:

http://www.gmsquarebody.com/forum/showthread.php?t=1559&highlight=removal


Damn, I know somebody else had a thread with real good pics of that stuff, can't find it to save my life....

 

[usar17]

Thank you guys so much. This is a big help to start.

 

[HotRodPC]

I'd still take you own pics too as you pull your donor apart. It's been said the Burb and Pick up underdash systems are a tad different. Likely do the rear air provisions, but just suggesting take pics anyway. It also wouldn't hurt to add those pics to his write up thread if you want. It may be helpful to other members to see the difference in the duct work for the Burb and Pick Up even though the difference is minor.

 

[oneluckypops]

ok I have a little bit more time so I will try to give you some pointers to get it done.

FIRST things FIRST, when you remove all the A/C parts from the donor truck. DO NOT disconnect ALL of the vaccume lines. There are only 4 vaccume connections that HAVE to be un hooked, the first one is the main vaccume block from the controller, The second one is the Recirculate door accuator located on the passengerside kick panel, the third and the fourth both run through the firewall, one of them is the supply line and the other actually runs inside the cowl (underneith where the wipers are) in opens and closes a flap for Fresh air. The vaccume harness will stay with the heater box when you remove it.

SECOND the electrical will simply all unhook from under the dash and transfer directly into your truck. The donor truck was of a different year on mine so there was 1 connector that I had to transfer ( cant remember which one it was) IF you have to be sure you cut the wires with enough to strip and be sure to SOLDER and shrink wrap your connections.

THIRD] after you remove all the ducting, heaterbox, and evaporator box. I would highly advise to make a cardboard template of the donor trucks firewall where the evaporator box mounts. If you take my advise on this you can simply plug the old holes for the heater hoses, and the big whole for where the air from the blower goes thru the firewall in the NON a/c cab with sheetmetal. After all the holes are plugged grind it smooth. Then you can place your cardboard template on your firewall and mark all the holes to be re cut out and drilled. after you do that its really as simple as fitting everything back into your truck.

oh yea do yourself a favor and DONT skimp, go ahead and REPLACE the Evaporator, and the Heatercore while you have everything removed.

Any questions along the way feel free to ask me or anyone else on the forum.

 

[89Suburban]

It's been said the Burb and Pick up underdash systems are a tad different. Likely do the rear air provisions....

Hmm, I never heard that before, I assumed they were the same.

 

[HotRodPC]

Hmm, I never heard that before, I assumed they were the same.

Why am I thinking it was you that said they were different? Wassup with that???

 

[89Suburban]

Why am I thinking it was you that said they were different? Wassup with that???

I dunno. I ripped mine out and had all those pics, and I thought at the time there was another thread with OLP and some other dude that had some really good pics and info in it for a p/u cab, I can;t remember all the convo in it though. I think threads like that should be combined and stickied so we can find them easier. There were some relly good photos and info in that one and I can't find it for chit. It would really help this guy out. I will keep looking.

 

[89Suburban]

Ahhh yeeeaaahhh, I found it!!

Foamypirates thread.


http://www.gmsquarebody.com/forum/showthread.php?p=57102&highlight=duct#post57102

 

[89Suburban]

The roof of the truck is double walled, so I'd try to keep it at 1/4 in into the ceiling of the truck and you should be good to go and not hit the 2nd layer or the outside roof of the truck. You can pull your dome light out inside the cab and get an idea of what I'm referring to.
Most of these trucks don't have headliners Jim. Of my 6 Silverados, only 2 had a headliner. That of course doesn't mean someone didn't take it out, but I installed the headliner from another truck into my 84. Makes a big difference on rain noise, and the interior sound is better too. Heater works better too in the winter. I'm hoping it also helps the AC when I get it working.

What a matta? 2/70 A/C aint good enough?