79 Trans Am AC system restore stock? or aftermarket?
 

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?

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.

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.

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.

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

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

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

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.

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.

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?

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

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.

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.

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

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.

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.

Thanks all for your previous help

Needing updated info as I had to take a year off the TA and I am getting ready to put engine bay together and having difficulty sourcing the AC parts.

Same as before looking for all needed components forward of the evaporator that I flushed and is good to go with rebuilt heater box and new heater core.

Classic Auto Air is currently not producing kits and I can’t find individual components on their site

Unfortunately our host site is hard to find parts also
Seems no one has complete only under hood kit forward of the evaporator

In sourcing parts it seems compressor, condenser and dryer should be easy to find but the hoses valves and required tubing is unknown by me as I have nothing to compare to.
Seems most hose kits are universal and I may need to source correct fittings to be crimped on to proper unknown lengths.

I believe the Sanden 508 compressor is a good choice but I will need to add and source mounting hardware to mount for the Olds 403

I have been looking for a list or schematic for all parts needed and the orings and seals necessary

Considering if all is worth the effort

Any additional thoughts or advice will be helpful.


Thank you

All I can offer is, if classic auto air were to sell kits again or even just parts, I’d avoid them. I have the kit they used to offer and I’m unimpressed.

That said, I thought vintage air offered a system that was for factory AC cars and covered the parts forward of the evaporator. I could be wrong.

When I install the Vintage Air units, I keep a few feet of the AMES flexible hose on hand. You can flatten it for clearance. The VA hose doesn't flatten.

Thanks for comments
I have been looking for under hood AC kits with no luck.
I acquired all underdash ducting and refurbished the underdash air box so I will be using stock ducting and controls
I plan on updating to 134a so I need the proper valving for updates to the stock system
Any ideas to source parts would be helpful
Thanks

What all exactly are you looking for? I might have everything you need including a bracket for a 403. Where are you located? I am outside Charlotte,NC.

I’d keep it stock,y I had my OG dryer rebuilt, it’s sealed and the guy acid dipped it to restore factory, that and a pressure switch has to swap out one day, then it’s back to stock. if you keep up with the AC it’s not a hard thing to keep running.
I bought the both machines to service it and a 30 lb tank of R12

This is what I have that was in the car when I purchased it (see Photos).

I am in Minnesota - 20 minutes north of Minneapolis 55014.

I have a new heater core installed - I have flushed the Evaporator and have rebuilt the heater box and all inside all actuators work well. - I am sourcing all new forward of that. I have sourced and heard that the Sanden Compressor is the way to go. It comes with mounts for the 403. I also found a parallel flow condenser that is supposed to come with a compressor safety switch, the dryer, all hard and soft lines, and mounting hardware. I assume the Orifice Tube is included with that as well. The compressor comes already filled with the correct oil depending on what system I do - R-12 or 134a.

Not sure what else I need. I may be missing alot.

I can send links to the parts I have found later.

Thanks

Sounds like you have everything you need if the flexible hoses attach to the metal hard lines coming from condenser.

You are actually not missing much.

If it were me I would buy the proper accumulator for your application (20 bucks), buy the hose assembly for your car and use the R4 compressor. Brackets are readily available from any car that came with the R4 compressor from 1979 to the late 80's with a 307 olds engine, they will directly bolt on. Any Olds, Buick, Pontiac, Cadillac mid to full size were available with the R4. Your favorite parts store has R4's in stock for around $200.00 brand new(not rebuilt).

Your A/C will be Ice cold.

If are wanting help going this route PM me and I would be glad assist.

I like to know the best option before I start the process - which is why I am putting this out there for input and feedback.

I would prefer it to be plug and play and not have to custom fit lines as some require.

Here are links to possible or similar to the components I am considering.

https://www.yogisinc.com/YVA021080

https://vintageair.com/1977-79-403-o...r-bracket-kit/ This is vintage air’s website but working with other vendors.

https://www.yogisinc.com/YACV508 You asked about all the options the main difference is brand and finish. We have had really good luck with the TBI brand.

https://www.yogisinc.com/YHK301

I am missing many of the AC components as shown in my photos and I have been doing a search online and cant locate a diagram of the 79 AC system. I am looking for all components necessary to complete the system and their stock install locations. Does anyone have a diagram or schematic of the 79 AC system of all components and their locations?

Once again looks like you have everything you need. Here is a picture of my hoses hooked up to condenser. What do you think you are missing looks like your parts list is complete
http://forums.maxperformanceinc.com/...1&d=1521473469

In addition to all I mentioned, I was not sure if or what I might be missing. And where the Orifice Tube went inline or if an additional expansion valve is needed and the location for those components.

The orifice tube is in that long smaller metal line running into the evaporator. I see with the condenser you have in your parts list there is a receiver/dryer, you probably should go with a style closer to what is on your car now just easier install for AC. You can get yours rebuilt if you are looking for 100% factory correct or you can order one that is similar. The only difference is OE lower tube was welded to the bottom of receiver/dryer where the newer style screws into the bottom.
https://www.firebirdcentral.com/1980...M2YkDMfpnbt7i0
The only thing possibly missing as I can see from photos is the OE wire harness that came with TA but not a big deal. Also the idle control might be missing on your carb. Mine was but with AC on, not causing drag another benefit with the Sanden compressor .

I have the harness from under dash to fan resistor with a new pigtail connector. I also ran a new fuseable link high speed wire from the alternator to the fan harness per wiring schematic. All fan speeds work with dash fan control. All gate actuators work with vacuum supplied to vacuum on dash controller.

I am missing the control wire to the compressor harness. I am unsure routing or wiring specs or source location. I was told it is just a 12volt power wire and ground wire to the compressor from the underdash harness.

Also, I didn't know I needed nor do I have the idle control wire from carb but I will cross that bridge if needed later as I have an aftermarket intake and am considering EFI.