74-78 ATC II to Manual A/C Inspection (and conversion??)

[Davea Lux]

That will save a ton of money. How do I test it after?

In the course of sourcing a new evaporator, were you able to determine if the ATC system and the standard system used the same one? If so, you might be able to transfer the evaporator form your ATC box into the standard air box. If it still holds a charge of gas, you already know that it is good.

Dave

 

[commando1]

In the course of sourcing a new evaporator, were you able to determine if the ATC system and the standard system used the same one? If so, you might be able to transfer the evaporator form your ATC box into the standard air box. If it still holds a charge of gas, you already know that it is good.

Dave

I slept on it and it's now moot. Stupid to reuse old stuff.

 

[cantflip]

I slept on it and it's now moot. Stupid to reuse old stuff.

I'm there in spirit, watching and learning. Be a while before I can make it to you with goodies to test/compare... try to resist the urge to toss the old parts... they may still have life in them. I haven't had a chance to see what your new stuff looks like in reality, but I have been disappointed more than a few times when I opened an aftermarket evaporator box... some of them look like they should be used in the manufacture of corn whiskey instead of cold air.

 

[1978 NYB]

I will have to rebuild mine eventually so any and all MASTER TUTORIAL from Stan is greatly appreciated!!!

 

[commando1]

I will have to rebuild mine eventually so any and all MASTER TUTORIAL from Stan is greatly appreciated!!!

View attachment 158063

Since your box is from a manual system and the box I just dissected is a manual system, I think I found a major problem with these boxes. The doors easily bind up from being able to be 100% free to fully open and close.
I SUSPECT (only) that may be why the biggest complaint of Formal HVAC systems is their "baby's breath-like" output.

 

[1978 NYB]

Since your box is from a manual system and the box I just dissected is a manual system, I think I found a major problem with these boxes. The doors easily bind up from being able to be 100% free to fully open and close.
I SUSPECT (only) that may be why the biggest complaint of Formal HVAC systems is their "baby's breath-like" output.

That is exactly the problem with my NYB. Temperature coming out of the vents is 38 degrees, blower motor spinning 1000 rpm's, and no air volume coming out of the vents!!!!

Can you provide a picture with an arrow pointing to the problem? I'm certain that is the problem or a big old rat nest blocking it.

 

[commando1]

Can you provide a picture with an arrow pointing to the problem?

Kinda hard right now. It's in a 100 pieces. lol.
Go back to the beginning of the thread and look at the pictures of the disection of the box. You can easily see the yuuge doors.

Commando1's Helpfull hint #88: The vacuum actuators are... Wait for it... GM of course.

 

[78Brougham]

used in the manufacture of corn whiskey

Mmmmm corn whiskey, sounds like you've had some experience there!

 

[SuicideDoorLincoln]

The atc's work so well with alot of vacuum going to them all the time. I added an electric vacuum pump inline pre reserve pot from a ford superduty vacuum initiated hub lock system. Would love to ad an engine mounted vacuum pump to this 440 but can't find any

 

[commando1]

The atc's work so well with alot of vacuum going to them all the time. I added an electric vacuum pump inline pre reserve pot from a ford superduty vacuum initiated hub lock system. Would love to ad an engine mounted vacuum pump to this 440 but can't find any

That's interesting information. I had not thought of that approach. Gonna do some Googling.

 

[SuicideDoorLincoln]

I figured this out driving the car in the southern missouri hills on the interstate. Everything works flawless when the car is idling, but when interstate cruising using alot more throttle vacuum drops off so much I can hear the vent doors changing. Sometimes the AC would go to the floor. An additional constant vacuum supply does wonders. Most vacuum loss is at the green and yellow vacuum switches, at the atc servo that moves like a snail

 

[commando1]

Never heard of these electric units. Got any key words I can use to start my Googling?

 

[traintech55]

Careful Stan, if it works you may start a run on electric vacuum motors.

 

[1978 NYB]

Get a Formal with manual A/C........

Tbere....I fixed the vacuum problem.

 

[73 T&C]

Reading along on this one..... as well.

Hmmmm vacuum pump.

I’m thinking it’s more like a million little leaks you can’t ever hope to fully correct. Vacuum motor seams, diphrams, hoses on both sides of the cowl, control switches and valves all with micro leaks 40 plus years on.

I had a 77 seville with a similar ATC system to what I’m finding in the NYB literature I’m seeing.

I had a throttle/Air con issue that was similar to what you mention. In fact, it would also clear up on deceleration when vacuum would spike. Engine vacuum at idle was a fairly steady 16” but would fall quickly when I opened the throttle and would take some time to build again in the air con controls under steady state. Under acceleration or when I would crack the throttle, I would loose air to the upper vents and it would then be warm.

So,,,, I put in a few one way valves into the actuator lines to the heater valve, mix door and direction door to which I carefully made a pinhole to delay the loss of vacuum and,,, bingo!

Priblem solved.

 

[commando1]

to which I carefully made a pinhole to delay the loss of vacuum and,,

You lost me. Where exactly?

 

[cantflip]

You lost me. Where exactly?

Sounds like check valves with a vacuum bleed... home made vacuum bleed... probably helped overcome the small leaks the old vacuum motors had developed.

 

[commando1]

?

So where do you drill this so called bleed hole?
I'm senile so be specific.

 

[cantflip]

?

So where do you drill this so called bleed hole?
I'm senile so be specific.

View attachment 168192

No idea... I imagine he pierced the diaphragm with a needle...

 

[73 T&C]

You lost me. Where exactly?

I made a small pinhole in the diaphragm inside the valve.