Installing Classic Auto Air in a '70 Charger

[68 Sport Satellite]

KD - gotta be a leak. Let the shop find it. I talked to John about the Vintage Air he installed himself in his yellow Baraccuda a few years ago and he told me it started blowing hot instead of cold a year after install. So you're not alone. Fingers crossed my system continues to blow cold since you took it to the shop for leak check.

 

[Kern Dog]

It really is frustrating.
This is the only classic car I've owned out of many...that I took the time and expense to ADD air conditioning instead of just removing it. I can handle the heat if I had to. I've worked in the heat all my life, I still have 3 other cars here that I drive all year round and they have no A/C.
The chilled air makes the car more enticing for the wife to join in on cruises and such. I admit, now that I have had it, it is a nice change from sweaty shirts.
It surprised me to learn awhile back that one could run the 30" vacuum to evacuate and burn up the internal contaminants and somehow still have a leak when it operates under pressure.
This comes down to the same situation I encountered with the Plymouth....I can install the system but I don't have a way to properly detect the leaks.

 

[Kern Dog]

I’d imagine that here are possibly some members on the forum that read through these tech threads and immediately know what is causing the problems we ask about.
Here is one for the brainiacs….
How can you explain these readings?

I have never seen a low side register this high. Of course, my experience is limited. I thought I recall hearing that the pressures can or will be equal when the engine is started.
The gauge to the left is the low side and is beyond 120, as is the pressure on the high side.
All my connections are good, the valves are open. I’ve checked it twice.
What are the chances that these Chinese gauges are AFU??

Of course I get off the couch to come out here at a time after the tech line closed at Classic Auto Air.
I can’t be the only guy that encounters that problem….the free time we get to do a task is also when the parts stores or tech lines are closed.

 

[1 Wild R/T]

So, the compressor clutch is not engaged? If that's the case the pressures have equalized... Low side looks higher than the high side but the reading at that portion of the scale isn't accurate... Either end of a gauge scale can be questionable.. 125-130 as an equalized pressure when the ambient temp is around 110 degrees may well be normal... What does it do when the clutch is engaged?

 

[Kern Dog]

The clutch was engaged. No weird noises, no belt squealing.

 

[1 Wild R/T]

The clutch was engaged. No weird noises, no belt squealing.

Well then, either the expansion valve is wide open... Or the compressor isn't actually pumping... Engine off, grab the clutch & turn it... How does it feel?

Gauges hooked up, engine on, engage & disengage the clutch, do the readings change?

 

[Kern Dog]

If I remember right, this compressor clutch usually stays engaged. I'll enlist Mary to operate switches and stuff inside, I'll be underhood watching things from there.
I can try to hand turn it tomorrow.

 

[1 Wild R/T]

You can unplug the clutch lead and simply jumper it to the battery terminal of the alternator... That way you have 100% control, you know when the clutch is energized & you see how it responds...

 

[Kern Dog]

During the install, I soldered the Compressor clutch power wire into the wires leading to the high/low switch:

I could use the jumper wire like so:

 

[1 Wild R/T]

Yes, but, instead of jumping to the second A/C lead from the control just jump it to 12v

 

[ckessel]

I'm getting further educated on this.

 

[Kern Dog]

I can hear it click on as I turn the key.

 

[Kern Dog]

This will be a little off topic but it still applies.
Today I was over at Rich's place, @CoronetDarter. Here is his Coronet:

He just finished the Classic Auto Air installation and it all looks fine. He put the vacuum pump on it along with these hoses and gauges:

The gauges wouldn't go over 10" of vacuum and bled off to zero when the pump was turned off so we figured it has a leak.
Part two:

This '68 Dart also has a CAA air system, installed by the previous owner.

We tried to pull a vacuum on it but the gauge numbers went positive.
It blows warm and the compressor clutch stays still. The high and low sides measured about 80 psi each with the engine running.
We bypassed the high-low pressure switch but it didn't encourage the compressor clutch to engage. The window in the manifold showed that refrigerant was present but who knows how much.

My own car still blows warm despite being charged 4 times since 2022.
The tech at CAA said that these systems have to be serviced different than OEM late model systems.
I don't know enough about this to just go my own way or call the guy a worry wart.
Dwight said that these systems are to be charged with the engine off. He said that the compressor clutch is to be spun 15-20 times before charging and after charging. The system takes a specific amount of refrigerant, no more, no less. It is either 24 or 28 ounces, I have it written down somewhere and it is clearly listed in the instructions. He said that you are not to invert any canister or tank to fill the system, it must be filled with the tank upright.
I have seen it done both ways so I don't know what is the advantage of doing the "right" way as per the CAA instructions and Dwight's advice.
Rich plans on doing the same thing that I do....To take his cars to a shop to close the book on the system.
We don't have the experience nor the leak detection tools to find leaks.

 

[Billccm]

I work at a auto parts store that has several semi retired and retired auto mechanics. They claim no rocket science in AC repair and service. They talk about pressure and air flow across the condenser and nothing else.

I'm not an expert, but our store rents the manifold gauges quite often and many people seem to successfully fix their AC. I think if you have refrigerant going low to high pressure you are removing BTU.

Not sure why there's a difference in service of vintage air versus typical car AC systems. Isn't vintage air based on a 1990s car AC system?

 

[1 Wild R/T]

Not sure why there's a difference in service of vintage air versus typical car AC systems. Isn't vintage air based on a 1990s car AC system?

Most 90's systems used an orifice tube, which means an Accumulator & a cycling clutch/compressor.. All the aftermarket systems I've seen are closer to a 60's-70's system with an expansion valve, a receiver dryer & the clutch mostly remains engaged unless pressures get way out of range....

Just to elaborate on Accumulator vs Receiver Dryer...
Receiver dryer goes in the high side liquid line & prevents refrigerant hitting the expansion valve as a gas...
Accumulator goes in the low side & prevents and liquid leaving the evaporator & hitting the compressor as a liquid... It gives the liquid a delay to change states....

 

[Kern Dog]

I have received some good advice on these threads but sometimes the stuff I read just fades from my memory. I apologize if I seem slow to grasp or quick to forget what advice I have received. Don't take it personal.
I thought I recall that it is normal for the high and low side to be equal at first but that the low side drops and the high side rises as the system starts working and the compressor engages. That is what I remember my own car doing. This didn't happen with his Dart.
What is odd is that we did not know that the Dart actually had refrigerant in the system. We went to pull a vacuum and the vacuum pump oozed a yellowish liquid from the vent tube so we turned it off.
I know that many times there are guys that tell you that you have to do it the correct way for the system or part to function correctly yet you do it different and it all still works.

 

[1 Wild R/T]

I have received some good advice on these threads but sometimes the stuff I read just fades from my memory. I apologize if I seem slow to grasp or quick to forget what advice I have received. Don't take it personal.
I thought I recall that it is normal for the high and low side to be equal at first but that the low side drops and the high side rises as the system starts working and the compressor engages. That is what I remember my own car doing. This didn't happen with his Dart.
What is odd is that we did not know that the Dart actually had refrigerant in the system. We went to pull a vacuum and the vacuum pump oozed a yellowish liquid from the vent tube so we turned it off.
I know that many times there are guys that tell you that you have to do it the correct way for the system or part to function correctly yet you do it different and it all still works.

Probably refrigerant oil with leak detection dye in it... To much oil can be just as much of a problem as to little oil... It plugs the expansion valve & the pressures go haywire...

 

[1 Wild R/T]

This will be a little off topic but it still applies.
Today I was over at Rich's place, @CoronetDarter. Here is his Coronet:

View attachment 1703762

He just finished the Classic Auto Air installation and it all looks fine. He put the vacuum pump on it along with these hoses and gauges:

View attachment 1703763

The gauges wouldn't go over 10" of vacuum and bled off to zero when the pump was turned off so we figured it has a leak.
Part two:

This '68 Dart also has a CAA air system, installed by the previous owner.

View attachment 1703761

We tried to pull a vacuum on it but the gauge numbers went positive.
It blows warm and the compressor clutch stays still. The high and low sides measured about 80 psi each with the engine running.
We bypassed the high-low pressure switch but it didn't encourage the compressor clutch to engage. The window in the manifold showed that refrigerant was present but who knows how much.

Did you test for power? could be the fuse is blown, or somethings unplugged.. Try jumping 12v to the clutch, bet the pressures change...

 

[Kern Dog]

We used a jumper wire to bridge the high-low switch but didn't think to run a jumper right to the battery.

 

[CoronetDarter]

Did you test for power? could be the fuse is blown, or somethings unplugged.. Try jumping 12v to the clutch, bet the pressures change...

Talked to Dwight today at CAA and he gave a couple of troubleshooting ideas. The Dart's ac system is at least 12 years old and its release was prior to CAA migrating over to an electrical/digital operating system which uses a microchip to calibrate the unit's function. This one is cable driven and uses the original OEM controls. As the user slides the Mode lever across the slot, a crank arm contacts one of two microswitches. Sliding the lever while engaging the fan will send 12V to the Hi/Lo switch, and eventually to the compressor if the ac pressure falls within a certain range.
One issue could be that the crank arm cable is misadjusted and the crank arm is not aligning with the microswitches. He also recommended testing the connections at the unit's thermostat.

Regarding the Coronet, Dwight is almost certain the leak is in the engine compartment, either an O ring fitting or crimp. Either reason is a bit disheartening because Greg and I spent a lot of time mapping out a clean install for the hardlines and hoses. All the crimps, fittings, and O rings are new and the O rings were lubricated in mineral oil. This was my first time ever using the hydraulic hose crimper; every collar seemed to crimp down just fine. At this point I'll probably use Greg's ac shop; they've worked on his Charger and Dwayne's Satellite.