[i4abuygto]

I need help with recommendations to get the AC working in my 79 403 TA.

I am putting my 79 TA interior back together and I want to get the AC system back working. I have the heater box installed with a new heater core, fan, resistor, and relay. I have an existing evaporator coil that has been flushed and holds pressure that I would like to use if possible. Can I use anything of what I have existing?

Attached is the photo of what I have- nothing forward of the dryer as shown in the photo.

I know I need the compressor and condenser and all the plumbing from the condenser back to the firewall.

I have a good wiring harness from the dash controller to the resistor but nothing forward of that to the compressor. The high-power fan feed from the alternator is working and the blower Fan blows well on all speeds. The vacuum gates in the under-dash ducting system have been fixed and work with the dash controller.

I dont have any of the compressor mounting brackets for the 403.

What is the best way to approach this to get the AC working for the least amount of cost?

Would I likely be able to find some used rebuildable components or is an aftermarket system my best option?

[Scarebird]

I was not impressed by the Vintage Air setup.

[bhill86]

I installed a Classic Auto Air system in my 77 400 being in a similar situation as you. I was missing all components beyond the evaporator core but flushed mine, it had no holes and everything under the dash was present and worked well.

I did not want to use a vintage air system (though people seem to like it) because I had all of the above mentioned items in working order already. I also don’t like the idea of tube ducting vs the factory stuff not to mention the hassle of replacing everything. I don’t believe at the time VA offered a retrofit kit for an AC car but you might be able to buy the components individually.

That said, I opted for the CAA Kit. It included the compressor (modern sanden), all of the lines, the accumulator/drier and a parallel flow condenser. It’s also 134a and it ran me around $1200 I think. Installation was fairly easy but I have some gripes in the fit and finish department. The compressor bracket is ugly and unpainted. I still need to remove and paint mine. The design of the bracket isn’t ideal either. I had really bad belt flutter initially. That seems to have corrected itself after some time. I also made a small pedestal bracket to add some rigidity to the compressor. I’m not sure how much that helped or didn’t.

The hard lines they provided didn’t fit the best either. I’d have to go back to my TAC post if it’s still there to recall exactly what the issues were but I remember one hard line was too long, one hose was almost too short.

Lastly, the charge was a little tricky to get right. It’s possible a competent AC shop could perfect it but I opted to charge myself since I was getting quotes of $200 to fill the system. It does blow cold but I think there is room for improvement. One thing I would’ve don’t differently was install a variable orifice tube instead of a fixed.

I should note that Vintage air sells a different compressor bracket that looks like it would work better that could be used with the CAA setup I believe. I planned to try that but opted not to since my belt flutter seemed to disappear.

CAA’s customer service was also severely lacking but this was around COVID times or just after the peak so I’ll make an assumption that is part of the cause and hopefully things have gotten better.

Hope this provides some insight.

[hgerhardt]

Since the under-dash parts and evap are the most complex sub-assembly of all, I'd use that and piece together the rest of the parts underhood.

To avoid the aftermarket, kludgy compressor/mount, I'd use a junkyard Olds compressor mount for an A6 and get a new A6 from Alma Products who now has the GM tooling for that compressor. Make sure the compressor has PAG oil in it if going R-134a. I'd also get a parallel-flow condenser.

Yeah, the A6 is heavier than a Sanden, etc, but it'll last forever and look "correct", as well as have good belt alignment.

[i4abuygto]

I installed a Classic Auto Air system in my 77 400

That said, I opted for the CAA Kit.

On the Classic Auto Air website I could only find the latest GM model for a Camaro complete system for a 1978. The firebird years I found were for the late 60s only. - is there a link to the CAA kit?

Thank you.

[bhill86]

Sorry, here…. https://www.originalair.com/engine-compartment-gm

It’s under original air group which is a part of classic auto air.

[ta6point6]

I used original air as well and thought fit was good but the ac mounting bracket was not painted( as mentioned) so do that first. With the sanden compressor I did not need to add a idle speed motor to carb. The sanden compressor does not drag down motor like stock compressors. I have a different opinion on OE compressors, they leak and fail at a higher rate then sanden compressors. I used my original evaporator just flushed it and everything is working fine. My biggest complaint is the OE fan motor does not create enough flow compared to modern vehicles. On hot days fan motor is in high the entire time
I started out with an original rebuilt A6 compressor from Napa and went through 2 in 2 years. Here is the kit I used
https://www.originalair.com/77-81-fi...ile-v8-stage-1

[bhill86]

I agree, my fan stays on high, likely max (recirculate), almost indefinitely on hot days. I’ve read about n this forum of people using a different fan that blows more air but I don’t think I ever saw a definitive solution to that.

[hgerhardt]

Originally Posted by ta6point6

.........I started out with an original rebuilt A6 compressor from Napa and went through 2 in 2 years. ...............

And there's the problem. I said get a NEW one from Alma Products, who own the original GM tooling. They are not cheap, however: https://coldhose.com/products/new-al...44110452031743

Also note that these A6's ship with mineral oil. To use with R-134a, you need to drain that and replace with PAG...did you happen to check that with your Napa units, or were you running R-12?

And as far as "more" HP required to rotate the A6 vs a Sanden--they're both axial piston compressors with a swash plate to drive the pistons--so if the A6 needs more HP, then it has a larger displacement and pumps more refrigerant. It's the 455 of the A/C compressor world!

The only reason I push the A6 is because the Sanden compressor with all its universal mounting ears and bracket is so ugly. It screams aftermarket.

Best would be if someone were to design a NICE bracket to hold a modern Denso compressor. That would be ideal.

[i4abuygto]

Thanks guys - great info here.

With the systems in the above links - will all components to make the system work be included in the kit from the evaporator coil forward to the condenser?

I will need to get the harness that goes forward to the compressor from the existing harness that connects to the harness coming through the firewall. Will all the components with the new system work with the stock wiring harness?

[ta6point6]

Originally Posted by hgerhardt

And there's the problem. I said get a NEW one from Alma Products, who own the original GM tooling. They are not cheap, however: https://coldhose.com/products/new-al...44110452031743

Also note that these A6's ship with mineral oil. To use with R-134a, you need to drain that and replace with PAG...did you happen to check that with your Napa units, or were you running R-12?
~I drained oil and used pag instead as I was using R-134. A new unit looks interesting but I imagine they still leak out the front of seal. That is how these A6 lubricated the seal. So that is why you see many A6 equipped cars with that oil stain on top of hood.~

And as far as "more" HP required to rotate the A6 vs a Sanden--they're both axial piston compressors with a swash plate to drive the pistons--so if the A6 needs more HP, then it has a larger displacement and pumps more refrigerant. It's the 455 of the A/C compressor world!

The only reason I push the A6 is because the Sanden compressor with all its universal mounting ears and bracket is so ugly. It screams aftermarket.
~I agree with you there the Sanden does look out of place under the hood but changing spark plugs is a lot easier with a sanden.~

Best would be if someone were to design a NICE bracket to hold a modern Denso compressor. That would be ideal.

There also has to be a weight savings with sanden over A6 as well

[bhill86]

Originally Posted by i4abuygto

Thanks guys - great info here.

With the systems in the above links - will all components to make the system work be included in the kit from the evaporator coil forward to the condenser?

I will need to get the harness that goes forward to the compressor from the existing harness that connects to the harness coming through the firewall. Will all the components with the new system work with the stock wiring harness?

Without rereading the stage 3 kit description, my stage 2 kit includes everything except the thermal switch if I remember correctly. (Different than the low pressure switch which is included). The wiring was simple. One wire (hot) from the factory harness to the compressor which is grounded through the bracket/engine. Now, since my AC stuff was all gone when I bought the car I could be wrong on this but if I remember right the factory setup included a two terminal plug for the compressor to ground the compressor which split off to a ring terminal I think went to the compressor bracket. I think that also provides ground for the blower fan. Someone before me reattached that ground elsewhere on my car to maintain the blower fan. So you’ll have to decide how you want to deal with that ground and powering the compressor.

Your two options. Would be cut the factory plug off, ground the black wire somewhere and run the hot to the new compressor. Or, I don’t like altering things permanently if I can help it so I’d probably make a jumper to plug into the factory plug then run the “new” wire(s) wherever you want.

[bsblguy]

I used the original air kit on a '78 and '79 and it works very well. Evap, condenser, compressor, all hoses. Everything needed. I do not like their compressor mounting bracket so I bought a vintage air bracket that looks much better. I did use a vintage air conversion kit on a '77 and works much better than factory air but my foot hits the vent duct by the gas pedal. My only complaint.

[Skip Fix]

The little rotary compressor in my 81 actually works pretty decent and easier to change plugs than the A6 that was on the 78!

[Trevor78]

Originally Posted by bsblguy

I used the original air kit on a '78 and '79 and it works very well.
my foot hits the vent duct by the gas pedal. My only complaint.

Is that a feature of the conversion, to have a floor ducting there? Or stock? Mine doesn't use any of that those.

I like my stock setup, the whole reason I went that was way for original appearance and at the time there was limited aftermarket anyway and still largely universal. I also started with nothing whereas sometimes that's enough of a reason to get new everything. Mine can still be adjusted down enough to freeze and still cycle so it certainly has the cooling capability, it also has the weight and perhaps limited economy. I doubled the engine HP so I'm not too worried about that! If the compressor ever plays up, they are hugely common and standard to just put another one on, not always the case with some aftermarket setups that come and go, Sanden is fairly safe and common. Comes down to the guy and what he wants and access to either setup.

[bsblguy]

the vintage air unit has flexible hoses run to all the vents. the drivers side vent comes out of the plenum right by the gas pedal, I have it ty wrapped as far away as possible but still hit it with my foot at times. the '79 I am doing right now I found all the pieces I was missing and putting it back to original the than the compressor.