Suburban rear AC retrofit

[notchbackgta]

I have gone back a lot of pages looking at all the AC threads and I haven't really found anything regarding retrofitting rear AC into the Suburbans. Mine has neither and, for survival, I need AC. I will put in a Classic Auto Air in the front, but I don't want to go through the hassle of trying to find a factory AC for the rear.
I am wondering what factory units from later vehicles may have been fitted by other people? I looked at a rear AC unit from a 90's Burb, but it looks like it sticks out too far and it blows the air up through a duct in the C-D pillar, whichever. But if someone has made that work somehow I'll give it a try.

And please don't say to use Google, been there already. I think disabling the search on the site was the worst possible thing they could have done, it cripples you if you only want to search one specific forum. Without being told, I know why they did it though

[magicoolbus]

Hi, quite a timely post. I am putting the finishing touches on my front and rear a/c in my burb. I installed a vintage air unit in my burb many years ago (over 10), and was quite happy with it, but I always knew I could do better.

I have been doing a resto on the burb for the past several years and have sourced a rear unit out of a early 80's burb. The fit did require a bit of modifications, but just tonight I was able to charge the system and get quite cold air out of the front and back. I am using an electric 2 speed rad fan from a Lincoln with the Hollister relay system-very nice set up indeed. I did my own wiring and relay set up to power up the rear with three speeds using this site for many of the ideas. I also sourced a factory rear air switch. I will try and go shoot a few pics. Dark now, but you should get the idea.

[magicoolbus]

Here's a couple of more bits of the puzzle.

In the first two pics you can see the routing of the a/c lines. Stock rear air drops down on the drivers side and goes underneath the vehicle near the third door and then routes up to engine compartment. With the 70/80's a/c, it drops on the passenger side making the routing easier. BTW, just got finished repainting the interior this weekend. Slowly putting things back in.



In the 3rd pic you can see the T fittings used to run the lines to the back. This was a bit of a PITA. Doing it over, I would have redone the lines completely to the front unit, as crimping on the vehicle is a bit of a challenge, takes two people, one to hold the fixture and one to run down the crimp.


In the 4th pic is Hollister Road's relay set up for the 2 speed Ford Fan. Can't say enough good things about the quality and functionality. Worth every penny and there were several.


Lastly is a pic of my first attempt at a semi complex relay system. I ran 12 gauge wire from engine compartment (junction block off of alternator, which is a 105 amp unit) all the way to a 20amp fuse block in back. I only ran 20 gauge wires from rear air switch to relay assembly.

[notchbackgta]

Thanks for the reply. Looks like you're doing a real nice job and attention to detail. I was hoping to get away from an overhead unit, but I guess that is the "best" way to do it since cold air sinks. I was thinking something that stayed in the side panel or something. I may just have to go to the yard and start pulling interiors apart with vehicles that have rear air and see what I can find.
I can always go for your method though. What is the purpose of the relay setup in the back? Does that work the clutch for the compressor?

[magicoolbus]

The rear relays are to deal with the long wire run from front switch. As I mentioned, the small 20 gauge wires from switch can't handle the current required to run the fan. The fan will run on high speed when it gets 12 volts, notice the flat plug in the side of the air box, that coil is used to step down the voltage allowing slower speeds.

[Cumminpwr11]

I like your rear air housing much better than the factory unit in my 72. Looks real good. My vintage air stopped working for I need to find a repair guy to fix it. Las Vegas summers are no joke and I need some cold air!

Chris

[Average Joe]

Nice work!!! This is the kind of thread that belongs in truck FAQ. Thanks for taking the time to document this Magicoolbus.

[reichdav]

Question about my 71 GMC w/ tailgate: Plastic housing (with GM on multi-speed fan knob) runs from front to back with diffusers along the way. Is this a factory unit? Maybe from a different year? Thanks.

[LockDoc]

Originally Posted by reichdav

Question about my 71 GMC w/ tailgate: Plastic housing (with GM on multi-speed fan knob) runs from front to back with diffusers along the way. Is this a factory unit? Maybe from a different year? Thanks.

I removed one like that from a '72 Chevy Suburban. It was stock, but I'm not sure what years the full length ones were used.

LockDoc

[53burb]

The full length ones were used from 67-71. 72 is when they started the rear only units.

[53burb]

This post has some pics in it of the two different units used....67-71 & 72 only. http://67-72chevytrucks.com/vboard/s...ad.php?t=68814

[reichdav]

I appreciate the info. I would have sent pics but my 9 yr old grandson wasn't available.