Author Topic: Factory A/C works!! Well, I mean it mostly does  (Read 299 times)

Maxthe222

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Factory A/C works!! Well, I mean it mostly does
« on: May 09, 2019, 05:45:56 AM »
It happened....

By Jove it happened, the factory A/C system is back in the car and to my shock, the compressor works and makes some great, cold air! Everything seems to be working really well so far! There are some kinks, such as the compressor shutting off after a few seconds, I think this is due to the pressure switch being dodgy and rusty and old. (The thing circled in white) Even then, it still consistently keeps cold air going, and you can see the condensation forming on the pipes!

The other thingy is, the blower fan maybe isn't working 100%, you can hear it running (sounds fine), you can hear the air flow/moving through the dash or something, but the problem is, air seeps out of the vents, but doesn't blow out of the vents, like there isn't a strong air flow. But you can feel the air is cold around the vents and dashboard.

Maybe it's blocked? Looked at some old threads, some solutions were just plug the thing in properly, or buy a new blower motor. Any other suggestions? I think there is a vacuum line I haven't got plugged in, i'm not sure what exactly it's for, but it's for something? (Circled in red)



And what did I learn?
1. Be careful getting that orifice tube out, that thing broke into a million pieces and it was a nightmare to get out.
2. Know what cables go where before you decided to put them into things that look like somewhere they should go.
3. That whole thing was a lot scarier than it looked, turns out it's easy enough if you have all the parts! It was mostly a plug (vacuum clean) and play!

I also can't stress enough, how helpful this guide was. To anyone hooking up their factory A/C system again, this is the proverbial bible for that. There's no write up like a Aus78Formula write up. Cheers Ben!  :-P

https://www.78ta.com/HTAF/index.php?topic=37312.0
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula ???

Grand73Am

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #1 on: May 09, 2019, 07:09:25 AM »
The vacuum line circled in red needs to be connected to manifold vacuum. It supplies vacuum to your heater/ac control panel, so the box doors operate when you make a selection. Probably the main reason that you aren't getting much air out the vents since the doors aren't working.
Steve F.

firebirdparts

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #2 on: May 09, 2019, 07:35:52 AM »
Awesome!

The compressor has to shut off to prevent freezing.  You can't interfere with that.  If it doesn't stay cold, then you need to hook up some gauges and that will tell you what might be the problem.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

1979 Black and Tan

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #3 on: May 09, 2019, 09:40:26 AM »
that Dryer looks like it has seen better days...if you open up the system the dryer needs to be replaced

if you plan of using R134a you will need a different Pressure switch for that refrigerant

I would also replace all the O rings
1979 Trans Am
100% California Car, originally Atlantis Blue/ Black...All Original Unmolested 403, TH350, 2.41
63,300 orig. miles
1971 Chevy K20 4x4

b_hill_86

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #4 on: May 09, 2019, 10:37:07 AM »
Not to hijack but since it was mentioned about the system being open, if the evaporator lines have been open but capped is it still likely that the evaporator should be replaced? And would open lines on the condenser require it to be replaced also?

Thanks for the post though Max. It’s just another piece that may help me get my AC going again eventually.
-Brian-

1977 Trans Am 400 4 speed

Re: Factory A/C works!! Well, I mean it mostly does
« Reply #4 on: May 09, 2019, 10:37:07 AM »

1979 Black and Tan

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #5 on: May 09, 2019, 02:53:26 PM »
Not to hijack but since it was mentioned about the system being open, if the evaporator lines have been open but capped is it still likely that the evaporator should be replaced? And would open lines on the condenser require it to be replaced also?

Thanks for the post though Max. It’s just another piece that may help me get my AC going again eventually.

the only time you need to replace the evaporator or condenser is if they leak ..
1979 Trans Am
100% California Car, originally Atlantis Blue/ Black...All Original Unmolested 403, TH350, 2.41
63,300 orig. miles
1971 Chevy K20 4x4

FormTA

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #6 on: May 09, 2019, 03:32:43 PM »
The dryers need replacing because the have desiccant in them that absorbs moisture.
79 Trans am 301 (work in progress) LS swap n progress
79 Formula 301 (Work in progress)
67 RS Camaro (Work in progress)
See the recurring theme???

Maxthe222

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #7 on: May 09, 2019, 03:51:30 PM »
Oh probably should mention that's an old photo from like a week or two ago. It has a new dryer on it now, aside from that and the o-rings and orifice tube, I didn't replace anything else. It is now running on R134a. The dryer was this kinda dodgy afternarket one, the fitment was a but weird but it fit with a bit of wrestling. It is much smaller in diameter and height than the factory one.

Condesor wasn't plugged up or sealed when I got it, but we cleaned it out anyway and it works. Same goes for all the lines, I replaced the foam bits but that was really it. However, the car had all the HVAC pipes and holes etc sealed with caps when I got the car from the states, and the compressor was sealed tight with this thick tape, so that probably helped a lot.

I think the only thing you really need to worry about is the compressor working. Wether it be from people implying that it'll never work or most people just leaving them off the car for too long, that seems like main point where things could go wrong. Everything else is just some metal pipes at the end of the day.

And yeah that's what they said about the compressor shutting off, I wasn't 100% sure that was true, but it made sense. The pipes at the back of the compressor were getting very cold very quick.

A-ha! that's what we thought about that line! We just had no idea where it went. It's a 403 Olds, do you know exactly where that goes on? We plugged in a few more vaccum things on the intake as we hooked up the Cruise Control as well. Yet to see if that works well, but everything was hooked up willy-nilly before so there were a ton of reasons why the Cruise wasn't working.

I'll put up some pics to explain stuff soon.
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula ???

Grand73Am

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #8 on: May 09, 2019, 05:30:46 PM »
There's a manifold vacuum port on the intake behind the carb, as shown in the top pic. That's what I use for the black vacuum line to the heater/ac controls.

The vacuum line is supposed to have a check valve connected to it, and then a vac hose from the valve to the manifold vacuum port, as shown in the bottom pic.

IMG_1772 - Copy (2) by grand73am, on Flickr
IMG_4320 - Copy (2) by grand73am, on Flickr
Steve F.

b_hill_86

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #9 on: May 09, 2019, 05:32:25 PM »
Thanks. I had just read that if the condenser or evaporator lines were left open to the atmosphere and/or dirt had gotten inside  they should be replaced. How’d you clean it out?
-Brian-

1977 Trans Am 400 4 speed

Maxthe222

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #10 on: May 09, 2019, 08:09:14 PM »
Thanks G/A, very helpful pics! What's a check valve and if I don't have it how much of an issue is it?

Also just blew in the bottom part of the compressor with a air compressor and same goes for the evaporator box, if stuff starts coming out then you'll likely need some fluid or cleaning agent to go through it and purge it out. If all that air pressure from the compressor isn't blowing it out, then it's probably not going to come out when the A/C is running.
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula ???

b_hill_86

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #11 on: May 09, 2019, 09:33:56 PM »
I think the check valve is so when you step on it and the vacuum drops because the throttle blades are open your blend doors stay put while the vacuum is temporarily low. They’re available for cheap if I remember right. I just bought one for my car last year.
-Brian-

1977 Trans Am 400 4 speed

b_hill_86

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #12 on: May 09, 2019, 09:35:32 PM »
I don’t remember paying this much but here is one.
https://www.firebirdcentral.com/mobile/Product.aspx?id=48277
-Brian-

1977 Trans Am 400 4 speed

Maxthe222

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #13 on: May 10, 2019, 04:24:56 AM »
Cool, can I get a check valve at any old car parts shop? Only known local Pontiac parts places are Chev Parts or Ponti-World (shudder). They don't seem to have one that is is similar, closest is this:
https://pontiworld.com.au/usgmsp/product_info.php?products_id=1701&osCsid=b67236490ba3a8f0749cc7f31162747b

Also think I should get a (wink) new (wink) pressure (wink) switch (wink) thingy (wink wink)  ;) If only I knew someone who had a few spares (that isn't Ponti-World) for sale...
 
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula ???

firebirdparts

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #14 on: May 10, 2019, 11:12:22 AM »
The check valve was used on millions of USA-made vehicles so you don't really need a GM specific supplier or item.  The Ford ones look just the same.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

Re: Factory A/C works!! Well, I mean it mostly does
« Reply #14 on: May 10, 2019, 11:12:22 AM »

FormTA

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #15 on: May 10, 2019, 11:59:02 AM »
Quote
Also think I should get a (wink) new (wink) pressure (wink) switch (wink) thingy (wink wink)  ;) If only I knew someone who had a few spares (that isn't Ponti-World) for sale...

Tourettes?
79 Trans am 301 (work in progress) LS swap n progress
79 Formula 301 (Work in progress)
67 RS Camaro (Work in progress)
See the recurring theme???

Maxthe222

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #16 on: May 10, 2019, 03:30:26 PM »
Wink ;)

And that's good, Holden is (was) one of Australia's biggest companies so they'll probably be around
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula ???

Maxthe222

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #17 on: May 17, 2019, 04:36:39 PM »
Ok so I was surprised but that valve did make a noticeable difference, the air flow was much higher, maybe some doors did open or something.

Some more questions though, is the blower motor meant to stay on while the key is in ignition? Also I can't help but feel the airflow sucks, I wasn't expecting like modern car air cannon level air flow, but surely more than just a weak breeze? Maybe the blower motor is on its way out.... Any other suggestions? Is it an easy thing to replace? Were they just that weak from factory?
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula ???

chewie37

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #18 on: May 17, 2019, 06:59:27 PM »
I'm by no means an expert, but I did pick up on a few things while resurrecting the AC in my '78 (400/auto) TA last year.  There may be differences in control setup from Pontiac 400 vs Olds 403, but I'll defer to others on that.
-  I don't believe the blower motor is ever truly 'off' when the ignition is on.  The bottom/lowest position on the blower control isn't off, just super low.
-  On the flip side, the top/highest position for the blower switch actually runs off a connection from the alternator.  On my car that harness extension was missing, so I didn't get full speed from the blower until I got that added back in.
-  Replacing the blower isn't exactly easy because of where it is, but it's doable and requires some patience.  Passenger side inner fender liner needs to come out to gain access.  You don't have to remove the wheel but it does give more room to work if you do.  I've also found that if you loosen the bolt that holds the bottom of the fender to the rocker panel  you can 'flex' the back end of the fender to make it a little easier to get the inner liner out.

Grand73Am

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #19 on: May 17, 2019, 09:22:10 PM »
Yes, the low speed blower is always on when the key is on. That's how they were designed to function.

If everything is working, the highest air flow is when the control is set to "max" or the blower switch set to high. You have to have the control set on one of the functions for the blower to blow medium or high. Of course, setting the control to "normal" for a/c, or "vent" for just vent air, you'll feel the most direct air from the dash vents.

Mine blows pretty good on high. 
Steve F.

Maxthe222

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #20 on: May 17, 2019, 11:57:54 PM »
Ok, I'm interested in this alternator thingy theory we've got going on here, Chewie. R.I.P btw. I checked all the lines down there, found one red/black wire that went from somewhere in the A/C area, under the air filter and to somewhere vaguely around the alternator...... maybe that's the one? I think it's plugged in. Do you have any pictures or kind of a better description of this harness?

I have no reason to assume the blower doesn't work. Out of all of the things on this car that miraculously work, I be surprised if the blower is really dying. I checked all the lines down there, found one red/black wire that went from somewhere in the A/C area, under the air filter and to somewhere vaguely around the alternator...... maybe that's the one? I think it's plugged in. Do you have any pictures or kind of a better description of this harness? I think the valve I've put on isn't appropriate to the system so that might also not be working correctly, there is a lot of plumbing underneath the passenger side, I wanna check on the heater core there too, i'll order the right valve from the states or something. Maybe a door or something still isn't opening or something's blocked/closed? Don't understand how a tiny little valve thing costs the same as a package tray shelf liner that's x50 the size. I've got the line plugged straight into a "T" piece that comes out of the vacuum tree G/A showed in the pics, so might be causing other issues. There is so many cables and junk under that air cleaner.....

The controls on the dash seem to work great, I never touched them or fiddled with the dash in anyway, I'm honestly surprised that stuff just worked when I plugged it back in. When I pushed the fan switch to high or low, it changes somewhat, you can hear something move or shift when you go between Hi and Lo.
« Last Edit: May 18, 2019, 12:10:54 AM by Maxthe222 »
1979 T/A Y84 WS6
1979 F/A W72 WS6
1971 Formula ???

Grand73Am

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #21 on: May 18, 2019, 07:31:59 AM »
Here's the wire that goes from the alternator to the high blower relay. It's a 12 gauge red wire off the alternator lug and has a connector that you can see that plugs into a 12 ga black wire that runs across the engine over toward the evap box, where it connects to red again in the harness, and plugs to the relay on the evap box, the red wire on the relay shown in the 2nd pic. So, if your wire from the alternator is damaged or missing, you can run a new 12 ga wire from the alternator to the red wire that's probably still in your harness over at the relay on your evap box.

IMG_2585 - Copy (2) by grand73am, on Flickr

high blower relay by grand73am, on Flickr
Steve F.

firebirdparts

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Re: Factory A/C works!! Well, I mean it mostly does
« Reply #22 on: May 18, 2019, 08:28:54 PM »
That wire has two connections in it, and it carries a lot of power, so they may get hot.  If the wire is there, and you don't get power, look at the connectors for signs of overheating.  You can wiggle them or clean them out but that problem might come back.  I just cut them out.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

Re: Factory A/C works!! Well, I mean it mostly does
« Reply #22 on: May 18, 2019, 08:28:54 PM »
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