63 Riviera AC vent doors opening and closing

[Riviera63]

23 minutes ago, KongaMan said:

Bill,

 

Your setup looks just like mine (only cleaner ). It looks like you've converted to R134A. What kind of temperatures do you see at the vents? 

 

BTW, where is that vacuum actuator on a 63?

 

And congrats on the fix.  IMHO, sorting out HVAC vacuum issues is one of the most frustrating jobs on these cars.

 

 

Yes, it was converted to R134A and also has a cycling switch. I'm not sure exactly what the temp is at the vents. I know the guys that work on my car checked it once and if I remember correctly it was in the 40's. They seemed to think it was fine. I am anxious to try it out and see how it does with good air flow. 

 

The vacuum actuator is next to the blower motor and to the left of the STV (or what's left of it).

 

Thanks for the pat on the back. I have had this car for 4 years now and I remember my first look at all of those vacuum hoses, the inside of the heater/AC control box on the fender and thought OMG what is this? I will never understand this mess! It was like looking at a book written in Chinese. Now that I have done some things with the HVAC system I think I have a good basic understanding of it works and it is not nearly as daunting as it once seemed. I'm not afraid of it anymore. It's been a lot of fun learning and doing new things to my car and seeing positive results. 

 

Bill

 

 

[KongaMan]

18 minutes ago, Riviera63 said:

Yes, it was converted to R134A and also has a cycling switch. I'm not sure exactly what the temp is at the vents. I know the guys that work on my car checked it once and if I remember correctly it was in the 40's. They seemed to think it was fine. I am anxious to try it out and see how it does with good air flow.

 

In the 40s should be good.  It would be interesting to know what the high and low side pressures are -- although bypassing the STV may affect that somewhat.

 

19 minutes ago, Riviera63 said:

The vacuum actuator is next to the blower motor and to the left of the STV (or what's left of it).

 

What we have here is a brain cramp. You wrote "actuator" and I was thinking "modulator" -- which is a different part entirely.  You didn't happen to encounter the modulator in your travels, did you?

[Turbinator]

1 hour ago, Riviera63 said:

 

 

Bob, 

 

Thank you for starting this thread. Reading this has helped me solve the problem I have had with my AC since I purchased my car. I too, had the same problem. Cold air, you could hear the blower fan going for all it was worth but,  low air flow at the AC vents in the car.  The maddening thing is that it would blow fine once in a great while. I went through and did several things that in hindsight were all good to do but, did not solve my problem. Including but not limited to replacing the #@%!*&! double diaphragm which was shot and removing the blower/heater box to replace the spring in there. I was fortunate to have small hands as I don't know how I would have gotten a couple of those screws out or back in on that heater box without a hoist to put the car on. This post that you and Tom were going back and forth on set me on the path to getting my car cooling the way it should. I just finished replacing the passenger side vacuum actuator on my car a half an hour ago. Problem solved! Powerful air flow out of all AC vents. Of course, now it probably won't get hot again until next summer. Here's hoping for hot weather for the trip to the ROA convention in Overland Park, KS next year. This is gives me a great sense of relief and accomplishment. This may not seem like much to the guys that know these cars and are mechanics but, for the "shade tree" mechanic it doesn't get any better than this. In my doing this replacement I ended up dealing with the #1, #2 and #3 vacuum switches because I did some vacuum line replacement. I talked to Jim Cannon about these. You should check all 3 to make sure that the plungers move freely. The grease hardens and they get sticky after all of these years. Spray some silicone in the vacuum ports and move the plungers back and forth to get them moving freely. Do not use WD 40. It may be that yours was just stuck. You can also put vacuum on the ports by mouth or with a vacuum tool to see if they work when you move the plungers. I had a couple that were pretty sticky. They are pretty easy to get to and remove. I hope you get to the bottom of your problems soon and thanks for indirectly helping me solve mine.

 

Bill

 

 

Bill, we are pretty much in the same boat regarding our air conditioning. I'm happy to learn you have the volume of air you want. Additionally, any info you can pick up on a thread that helps I'll vote for everytime. I understand you converted to the 134 A and you updated the STV ? Your temperature at 40 degrees coming out of the vents is cold enough for you then that is the right temperature. I've heard by word of mouth " spec" is suppose to be in the 30''s? I really don't know. I think my temp coming out of the vent was/is too low b/c the hoses freeze once in awhile. The hose doesn't freeze up but it gets ice on both ends.

I have a friend mechanic who is taking on the vacuum challenge. He Has narrowed down the vacuum leaks and we are in hopes of having a tight as humanly and mechanically possible. I stayed with the R12 and had the STV rebuilt by cold Air. Replacing the drier, muffler, A6 compressor, hoses(s), the R12 is pricey as well can add up. Oh, I bought the #1 vacuum Actuator switch and the  same vacuum Actuator you replaced as well. I have to buy the double diaphragm as well. Where did you buy your double diaphragm? 

We are closing in the AC challenge repair. My friend is doing the work. I assist by getting the parts and doing the step and fetch while he cusses at the system. I'm not close to being a shade tree mechanic, but some projects I can handle I'll go ahead and give it a go. There are other things I can hold my own, but auto mechanics is not my strong suite.

thanks for the tip on the sticky vacuum switches as they are scarce and when you do find a switch the price of the switch gets your attention.

RRB

[Riviera63]

26 minutes ago, KongaMan said:

 

In the 40s should be good.  It would be interesting to know what the high and low side pressures are -- although bypassing the STV may affect that somewhat.

 

 

What we have here is a brain cramp. You wrote "actuator" and I was thinking "modulator" -- which is a different part entirely.  You didn't happen to encounter the modulator in your travels, did you?

 

I don't know. I have no idea what a modulator is. Describe it to me and I'll see if I have one and where it's located. Thanks.

 

Bill

[RivNut]

Quote "Oh, I bought the #1 vacuum Actuator switch and the  same vacuum Actuator you replaced as well. I have to buy the double diaphragm as well. Where did you buy your double diaphragm? "

 

Go back and read post #11

[Riviera63]

24 minutes ago, Red Riviera Bob said:

Bill, we are pretty much in the same boat regarding our air conditioning. I'm happy to learn you have the volume of air you want. Additionally, any info you can pick up on a thread that helps I'll vote for everytime. I understand you converted to the 134 A and you updated the STV ? Your temperature at 40 degrees coming out of the vents is cold enough for you then that is the right temperature. I've heard by word of mouth " spec" is suppose to be in the 30''s? I really don't know. I think my temp coming out of the vent was/is too low b/c the hoses freeze once in awhile. The hose doesn't freeze up but it gets ice on both ends.

I have a friend mechanic who is taking on the vacuum challenge. He Has narrowed down the vacuum leaks and we are in hopes of having a tight as humanly and mechanically possible. I stayed with the R12 and had the STV rebuilt by cold Air. Replacing the drier, muffler, A6 compressor, hoses(s), the R12 is pricey as well can add up. Oh, I bought the #1 vacuum Actuator switch and the  same vacuum Actuator you replaced as well. I have to buy the double diaphragm as well. Where did you buy your double diaphragm? 

We are closing in the AC challenge repair. My friend is doing the work. I assist by getting the parts and doing the step and fetch while he cusses at the system. I'm not close to being a shade tree mechanic, but some projects I can handle I'll go ahead and give it a go. There are other things I can hold my own, but auto mechanics is not my strong suite.

thanks for the tip on the sticky vacuum switches as they are scarce and when you do find a switch the price of the switch gets your attention.

RRB

 

Bob,

 

The air was converted before I bought the car. The STV is not used in this conversion. It looks like it is there but, the inner workings are gone. The cycling switch was added after I had the car when it was getting a new heater core and radiator. I had the guy also check over the air as well. I can't even pretend to understand all of these things. I believe the cycling switch was added because the STV was inoperative. 

 

The same diaphragm you got for the passenger side is the same diaphragm you use to replace the double diaphragm because those are no longer available. That conversion is discussed in other threads. Jim Cannon has commented on this in those threads. I followed his lead when I replaced mine.

 

Bill

[Turbinator]

Ed, without too much fear I'll dare to be slow:

do I need  2 each of what is described from Classic Buick parts? There are two pics in the catalogue. Is one pic the front and one pic the crack of the same diaphragm?

i get the item shown is the outside air diaphragm. Is the " recirculating air diaphragm" the same as in the picture?

I appreciate your patience and assistance.

RRB

 

 

 

 

 

 

Model application: Most A/C models as required for outside air inlet, defrost or diverter door. 4″ black plastic, 2 staggered-ports.GM #1998905 (1st type was white plastic & 63 Riviera 1st type lower was metal 2pc.) 63-65 Riviera uses 2 of these for upper and lower

 

[Jim Cannon]

 

39 minutes ago, Red Riviera Bob said:

 

<snip>

 

I understand you converted to the 134 A and you updated the STV ? Your temperature at 40 degrees coming out of the vents is cold enough for you then that is the right temperature. I've heard by word of mouth " spec" is suppose to be in the 30''s? I really don't know. I think my temp coming out of the vent was/is too low b/c the hoses freeze once in awhile. The hose doesn't freeze up but it gets ice on both ends.

 

Guys, frost on the outside of your A/C hoses under the hood is normal and GOOD.  It means that your suction line is very cold, which is what you want.

 

Having your A/C only blow in the 40's on max while driving is not cold enough.  I see mid-30s with R-12 running down the road with it 110 degrees outside.  When it is humid in Houston, I get fog blowing out of my center vent.  That's cold!

 

This is the main complaint of people with R-134a, not cold enough.  If you have an STV, you can lower the suction pressure a few psi.

 

If you are going to run R-134a, you need a condenser in front of the radiator that was designed for R-134a.  The rest of the system does just fine.

 

[Turbinator]

16 minutes ago, Riviera63 said:

 

Bob,

 

The air was converted before I bought the car. The STV is not used in this conversion. It looks like it is there but, the inner workings are gone. The cycling switch was added after I had the car when it was getting a new heater core and radiator. I had the guy also check over the air as well. I can't even pretend to understand all of these things. I believe the cycling switch was added because the STV was inoperative. 

 

The same diaphragm you got for the passenger side is the same diaphragm you use to replace the double diaphragm because those are no longer available. That conversion is discussed in other threads. Jim Cannon has commented on this in those threads. I followed his lead when I replaced mine.

 

Bill

Bill, I'm following you with your progress of what you have and what direction the AC was going when you got the car. I'm cool with that.

so, you bought two (2) vacuum actuators and converted them to work as the "double"?

thanks for your help.

[KongaMan]

1 hour ago, Riviera63 said:

I don't know. I have no idea what a modulator is. Describe it to me and I'll see if I have one and where it's located. Thanks.

Never mind, I found it.  (It's part of the dash controls).

 

FYI, the modulator is the control for the STV.  The STV controls the evaporator pressure, which, in turn, controls the temperature.  Not sure how (or if) it would be used when the STV is replaced by a cycling switch.  If it's no longer used, it's just another potential source for a vacuum leak.

 

They may have changed this setup, but it used to be that there was no temperature control on your AC when you replaced the STV with a cycling switch.  That is, the AC was either on or off.  When it was on, the compressor was either running or it wasn't.  When it was running, you got full cold.  When it wasn't, you got uncooled outside air.  There was no "I want it a little bit warmer", as temperature adjustment was disabled when the STV was bypassed.  To use the home HVAC analogy that was offered earlier, it would be like saying that if you have the AC on, it's going to be 58° in the house; there is no thermostat.

Edited August 16, 2017 by KongaMan (see edit history)

[Riviera63]

1 hour ago, Red Riviera Bob said:

Bill, I'm following you with your progress of what you have and what direction the AC was going when you got the car. I'm cool with that.

so, you bought two (2) vacuum actuators and converted them to work as the "double"?

thanks for your help.

  

 

Bob,

 

No, There is no double to be had or made. One single actuator (the same one as you bought for the engine compartment) replaces the double. With the double you had a vacuum line going to each diaphragm, giving you a choice of 1/2 open or full open. With the new actuator (which has 2 ports) you will have to make a choice between full open or 1/2 open. You will not have the choice as in the old set up. One of the lines that went to the old actuator will be plugged and not used. The other line you split by putting a "tee" in, creating 2 lines from that single line. These 2 lines you created will go on to the 2 ports of the new single actuator. If you want I can send you my e-mails from and to Jim Cannon on this. I'll try to find the thread that also discussed this. Thanks.

 

Bill

[1965rivgs]

3 hours ago, Riviera63 said:

 

 

Bob, 

 

Thank you for starting this thread. Reading this has helped me solve the problem I have had with my AC since I purchased my car. I too, had the same problem. Cold air, you could hear the blower fan going for all it was worth but,  low air flow at the AC vents in the car.  The maddening thing is that it would blow fine once in a great while. I went through and did several things that in hindsight were all good to do but, did not solve my problem. Including but not limited to replacing the #@%!*&! double diaphragm which was shot and removing the blower/heater box to replace the spring in there. I was fortunate to have small hands as I don't know how I would have gotten a couple of those screws out or back in on that heater box without a hoist to put the car on. This post that you and Tom were going back and forth on set me on the path to getting my car cooling the way it should. I just finished replacing the passenger side vacuum actuator on my car a half an hour ago. Problem solved! Powerful air flow out of all AC vents. Of course, now it probably won't get hot again until next summer. Here's hoping for hot weather for the trip to the ROA convention in Overland Park, KS next year. This is gives me a great sense of relief and accomplishment. This may not seem like much to the guys that know these cars and are mechanics but, for the "shade tree" mechanic it doesn't get any better than this. In my doing this replacement I ended up dealing with the #1, #2 and #3 vacuum switches because I did some vacuum line replacement. I talked to Jim Cannon about these. You should check all 3 to make sure that the plungers move freely. The grease hardens and they get sticky after all of these years. Spray some silicone in the vacuum ports and move the plungers back and forth to get them moving freely. Do not use WD 40. It may be that yours was just stuck. You can also put vacuum on the ports by mouth or with a vacuum tool to see if they work when you move the plungers. I had a couple that were pretty sticky. They are pretty easy to get to and remove. I hope you get to the bottom of your problems soon and thanks for indirectly helping me solve mine.

 

Bill

 

 

Bill,

  I`m quite positive you and I discussed the actuator at the St Charles meet! You must have been in shock looking at all the beautiful Rivieras! Lol...

  Tom

[1965rivgs]

20 minutes ago, Riviera63 said:

  

 

Bob,

 

No, There is no double to be had or made. One single actuator (the same one as you bought for the engine compartment) replaces the double. With the double you had a vacuum line going to each diaphragm, giving you a choice of 1/2 open or full open. With the new actuator (which has 2 ports) you will have to make a choice between full open or 1/2 open. You will not have the choice as in the old set up. One of the lines that went to the old actuator will be plugged and not used. The other line you split by putting a "tee" in, creating 2 lines from that single line. These 2 lines you created will go on to the 2 ports of the new single actuator. If you want I can send you my e-mails from and to Jim Cannon on this. I'll try to find the thread that also discussed this. Thanks.

 

Bill

Bill,

  I dont believe this is correct, at least not current. The double diaphrams are available. The double diaphrams have 2 ports, that`s what makes them "double". Maybe we have a lapse in understanding re terminology?

  Tom Mooney

[KongaMan]

I think that what Bill is saying is the the current diaphragms look like the old ones, but function differently.  The old ones had three settings: closed, partially open, fully open.  The new ones have only two: partially open and fully open.  IOW, one "port" is there only for cosmetic consistency (and a place to stick the now unused vacuum line).  No idea if that's accurate, but that should be easy enough to verify.

Edited August 16, 2017 by KongaMan (see edit history)

[Riviera63]

4 minutes ago, 1965rivgs said:

Bill,

  I dont believe this is correct, at least not current. The double diaphrams are available. The double diaphrams have 2 ports, that`s what makes them "double". Maybe we have a lapse in understanding re terminology?

  Tom Mooney

 

Tom,

 

I think we have a misunderstanding in terminology. When I say and from what I understand that, other people mean when talking about this topic, double actuator is referring to the original actuator that had 2 (double) single diaphragms, one stacked on top of the other. When I(they) refer to a single actuator, I am referring to the new actuator that even though it has 2 ports has only a single diaphragm.

 

Bill

[1965rivgs]

2 hours ago, Red Riviera Bob said:

Ed, without too much fear I'll dare to be slow:

do I need  2 each of what is described from Classic Buick parts? There are two pics in the catalogue. Is one pic the front and one pic the crack of the same diaphragm?

i get the item shown is the outside air diaphragm. Is the " recirculating air diaphragm" the same as in the picture?

I appreciate your patience and assistance.

RRB

 

 

 

 

 

 

Model application: Most A/C models as required for outside air inlet, defrost or diverter door. 4″ black plastic, 2 staggered-ports.GM #1998905 (1st type was white plastic & 63 Riviera 1st type lower was metal 2pc.) 63-65 Riviera uses 2 of these for upper and lower

 

Bob,

  I am not looking at any vendor sites for reference but just an FYI... the "outside air" terminology is generally associated with non AC applications and "recirculating air" is generally associated with AC equipped cars. In non AC Rivs there is a single stage diaphram in the same location as the AC/heat diaphragm on AC equipped cars (the one that controls airflow to the AC vents). The "recirc" diaphram on AC cars is located below the blower box on the pass side, hard to see from on top but very visible from below. This is also a dual stage diaphragm, same as the AC/heater diaphram on top. Hope this helps,

  Tom

[KongaMan]

14 minutes ago, 1965rivgs said:

 In non AC Rivs there is a single stage diaphram in the same location as the AC/heat diaphragm on AC equipped cars (the one that controls airflow to the AC vents). The "recirc" diaphram on AC cars is located below the blower box on the pass side, hard to see from on top but very visible from below. This is also a dual stage diaphragm, same as the AC/heater diaphram on top.

 

Just to clarify...  I believe that the 63 has two single stage diaphragms and one dual stage, while 64 (and maybe 65) has two dual stage diaphragms.  Is this not correct?

[1965rivgs]

25 minutes ago, Riviera63 said:

 

Tom,

 

I think we have a misunderstanding in terminology. When I say and from what I understand that, other people mean when talking about this topic, double actuator is referring to the original actuator that had 2 (double) single diaphragms, one stacked on top of the other. When I(they) refer to a single actuator, I am referring to the new actuator that even though it has 2 ports has only a single diaphragm.

 

Bill

Oh yes, I understand your use of the terminology now.

  Tom

[KongaMan]

1 hour ago, Riviera63 said:

I think we have a misunderstanding in terminology. When I say and from what I understand that, other people mean when talking about this topic, double actuator is referring to the original actuator that had 2 (double) single diaphragms, one stacked on top of the other. When I(they) refer to a single actuator, I am referring to the new actuator that even though it has 2 ports has only a single diaphragm.

 

Isn't that the opposite of the terminology that Buick uses in the service manual?  The 64 manual clearly calls a diaphragm with two ports a "dual stage vacuum diaphragm": "Two dual stage vacuum diaphragms (see Figure 11-80) and two vacuum disc switches comprise the vacuum circuit for the 4700"  The 63 manual doesn't make any such clarification in the illustrations, but it does in the text: " The #1 and #2 diaphragms are enclosed in a dual diaphragm assembly.  The #3 and #4 are separate diaphragms."

[Riviera63]

2 minutes ago, KongaMan said:

 

Isn't that the opposite of the terminology that Buick uses in the service manual?  The 64 manual clearly calls a diaphragm with two ports a "dual stage vacuum diaphragm": "Two dual stage vacuum diaphragms (see Figure 11-80) and two vacuum disc switches comprise the vacuum circuit for the 4700"  The 63 manual doesn't make any such clarification in the illustrations, but it does in the text: " The #1 and #2 diaphragms are enclosed in a dual diaphragm assembly.  The #3 and #4 are separate diaphragms."

 

I would not know what the 64 manual would say. I only have a 63 and the 63 manual. I have only used terminology that was used previously and currently by others on this forum to describe these items. It is not something I invented. I understood what they were referring to as I am sure others did too. I guess to me a "dual diaphragm assembly" means the same as a "double actuator" and it was confirmed to me when I pulled my old (insert your own term here) out. It had dual (double) diaphragms. I take it in this situation as double meaning 2 diaphragms and single meaning 1 diaphragm regardless of the number of ports and how they are labelled in a service manual. I think we are getting too much into semantics and missing the larger picture. The fact is that the old (insert your own term here) that goes under the heater box is no longer available. In order to replace this old (insert your own term here) you have to replace it with a new (insert your own term here) that is not exactly the same as the old (insert your own term here) therefore requiring some changes that are not the same as original but, basically gives the same function as the old (insert your own term here). The new (insert your own term here) is exactly the same new (insert your own term here) as was ordered from Cold Air Products that is used in the engine compartment by the blower motor because the old (insert your term here) used under the heater box is no longer available. All I know is I figured it out reading those terms used by others, I did it and it works. That's all I have to say about that. 

 

Bill

[KongaMan]

"Double" and "dual stage" are not synonymous.  And if you replace a dual-stage diaphragm with a single stage diaphragm with two ports (note the word "stage"; it's important), you're using a different part that behaves differently.  Much like gutting the STV and replacing it with a cycling switch, you have not duplicated the original functionality; you've changed it.

 

Please look at section 11-16 a and Figure 11-73 of the 63 manual.  They make a clear distinction between a single and a dual diaphragm.

 

To be clear, the 63 has two single stage diaphragms and one dual stage diaphragm.  If others refer to them incorrectly, that's on them.  There's no need to propagate their error.  To do so only sows confusion.

[Riviera63]

10 minutes ago, KongaMan said:

"Double" and "dual stage" are not synonymous.  And if you replace a dual-stage diaphragm with a single stage diaphragm with two ports (note the word "stage"; it's important), you're using a different part that behaves differently.  Much like gutting the STV and replacing it with a cycling switch, you have not duplicated the original functionality; you've changed it.

 

Please look at section 11-16 a and Figure 11-73 of the 63 manual.  They make a clear distinction between a single and a dual diaphragm.

 

To be clear, the 63 has two single stage diaphragms and one dual stage diaphragm.  If others refer to them incorrectly, that's on them.  There's no need to propagate their error.  To do so only sows confusion.

 

I did not say that double and dual stage are the same. I was referencing your statement about the 63 manual " The 63 manual doesn't make any such clarification in the illustrations, but it does in the text: " The #1 and #2 diaphragms are enclosed in a dual diaphragm assembly". I said to me a double diaphragm means the same as dual diaphragm, double=dual meaning 2  diaphragms put together to make one in that statement. Not that double and dual stage are synonymous. As far as the STV and the cycling switch go I never said that the cycling switch duplicated the function of the STV I only reported that it was done to my car no more no less. I and as far as I know others have never stated that the terms used by myself and others are the correct terms. No one is trying to propagate an error. It is merely a way to distinguish between 2 different items. We all understand it.  I think all of us that have 1963 Rivieras are clear that there are 2 single stage diaphragms and one dual stage diaphragm which is  comprised of two, 2, double, dual, dos, a pair of diaphragms hooked together to make one. I'm out.

 

Bill

[Turbinator]

4 hours ago, Riviera63 said:

  

 

Bob,

 

No, There is no double to be had or made. One single actuator (the same one as you bought for the engine compartment) replaces the double. With the double you had a vacuum line going to each diaphragm, giving you a choice of 1/2 open or full open. With the new actuator (which has 2 ports) you will have to make a choice between full open or 1/2 open. You will not have the choice as in the old set up. One of the lines that went to the old actuator will be plugged and not used. The other line you split by putting a "tee" in, creating 2 lines from that single line. These 2 lines you created will go on to the 2 ports of the new single actuator. If you want I can send you my e-mails from and to Jim Cannon on this. I'll try to find the thread that also discussed this. Thanks.

 

Bill

Bill thanks for your patience and assistance. I get it now. One vacuum actuator replaces two. The proper routing of the vacuum hoses you described is a big help.

I'm going to start to print out the guidance so I don't cause anyone to repeat themselves just for my benefit. Again, thank you for clarification.

RRB

[Turbinator]

3 hours ago, KongaMan said:

I think that what Bill is saying is the the current diaphragms look like the old ones, but function differently.  The old ones had three settings: closed, partially open, fully open.  The new ones have only two: partially open and fully open.  IOW, one "port" is there only for cosmetic consistency (and a place to stick the now unused vacuum line).  No idea if that's accurate, but that should be easy enough to verify.

Mr. Konga Man, thank you. I'm closing in on it. I appreciate your additional help by writing the solution in different words. I'm hopeful the items we are replacing 

will help make the system work closer to how it was intended to work,

RRB

[Jim Cannon]

The "double diaphragm" (stacked diaphragms) under the blower motor allowed Buick to have the recirc door (or the "fresh air in" door, if that's what you want to call it) be fully closed when the system is fully off, part open when the A/C is on High fan speed and Max Cooling.  This is as close to fully recirc that Buick offered.  In all of A/C positions and in all modes with heat, the recirc door is fully open (i.e. full fresh air flow from outside).  This is all in the shop manual.  (In today's modern car A/C, they offer full recirc.).

 

Personally, I like having full recirc on my A/C all the time, instead of cooling down the hot, humid outside air in Houston.  So that is why I modified my system to be open for heat (all fresh air) and closed for A/C (full recirc) by having no vacuum applied to either diaphragm (or either port of a 2-port diaphragm, like you use on the plenum on the firewall under the hood).  I don't use the partial open setting at all.

 

The spring pulls the recirc door closed (full recirc -- no outside air) if no vacuum is on a diaphragm under the fan.  Better than what Buick did for cooling.  BTW, they were concerned about carbon monoxide poisoning.  That's why they wanted to bring in the fresh air all the time.  No cat converter on these cars, lots of CO.  Be careful!

 

 

 

 

 

[Turbinator]

21 hours ago, Jim Cannon said:

 

 

Guys, frost on the outside of your A/C hoses under the hood is normal and GOOD.  It means that your suction line is very cold, which is what you want.

 

Having your A/C only blow in the 40's on max while driving is not cold enough.  I see mid-30s with R-12 running down the road with it 110 degrees outside.  When it is humid in Houston, I get fog blowing out of my center vent.  That's cold!

 

This is the main complaint of people with R-134a, not cold enough.  If you have an STV, you can lower the suction pressure a few psi.

 

If you are going to run R-134a, you need a condenser in front of the radiator that was designed for R-134a.  The rest of the system does just fine.

 

Jim, I appreciate the guidance regarding ice on my AC line. Just lower the suction pressure a bit to get rid of the ice. I have it.

RRB

[Turbinator]

6 hours ago, Jim Cannon said:

The "double diaphragm" (stacked diaphragms) under the blower motor allowed Buick to have the recirc door (or the "fresh air in" door, if that's what you want to call it) be fully closed when the system is fully off, part open when the A/C is on High fan speed and Max Cooling.  This is as close to fully recirc that Buick offered.  In all of A/C positions and in all modes with heat, the recirc door is fully open (i.e. full fresh air flow from outside).  This is all in the shop manual.  (In today's modern car A/C, they offer full recirc.).

 

Personally, I like having full recirc on my A/C all the time, instead of cooling down the hot, humid outside air in Houston.  So that is why I modified my system to be open for heat (all fresh air) and closed for A/C (full recirc) by having no vacuum applied to either diaphragm (or either port of a 2-port diaphragm, like you use on the plenum on the firewall under the hood).  I don't use the partial open setting at all.

 

The spring pulls the recirc door closed (full recirc -- no outside air) if no vacuum is on a diaphragm under the fan.  Better than what Buick did for cooling.  BTW, they were concerned about carbon monoxide poisoning.  That's why they wanted to bring in the fresh air all the time.  No cat converter on these cars, lots of CO.  Be careful!

 

 

 

 

 

Jim, thank you again.

RRB

[Bill Stoneberg]

I have learned enough from reading this thread to tackle my A/C on my Electra.  It has the same issues. Starting withe Check valve and will work my way to the actuators.  Compressor and the cool side works well, its just under acceleration or sitting at a light, it warms up. Sounds like same basic setup too.

[Turbinator]

On 8/2/2017 at 0:50 PM, RivNut said:

There's a very good system trouble shooting guide in the chassis manual.  LOTS of vacuum lines control the A/C system.  

Ed, the evidence is certainly there for me see spaghetti junction.?

[Jim Cannon]

3 hours ago, Red Riviera Bob said:

Jim, I appreciate the guidance regarding ice on my AC line. Just lower the suction pressure a bit to get rid of the ice. I have it.

RRB

 

No, Bob... if you have ice on the line, leave it alone.  It is normal, especially in a humid place.

 

If you are running R-134a and you do not have ice, if the outlet temperature of the air is not too cold, lower the suction line pressure a few psi.  You don't need to change anything, you are good.

[KongaMan]

3 hours ago, Bill Stoneberg said:

I have learned enough from reading this thread to tackle my A/C on my Electra.  It has the same issues. Starting withe Check valve and will work my way to the actuators.  Compressor and the cool side works well, its just under acceleration or sitting at a light, it warms up. Sounds like same basic setup too.

Those sound like it may be two different scenarios.  If it warms at idle, that might be related to airflow across the condenser.  Make sure that it's clear of debris, and make sure your fan clutch is working.  If it warms under acceleration, it may be a vacuum issue that directs air away from the evaporator or a defective check valve at the intake manifold.  If you have low vacuum at idle, that may also explain the first issue.

 

Does the air flow change at all?  That is, do you ever get get air from the heater vents when running the AC?

[1965rivgs]

22 hours ago, Jim Cannon said:

The "double diaphragm" (stacked diaphragms) under the blower motor allowed Buick to have the recirc door (or the "fresh air in" door, if that's what you want to call it) be fully closed when the system is fully off, part open when the A/C is on High fan speed and Max Cooling.  This is as close to fully recirc that Buick offered.  In all of A/C positions and in all modes with heat, the recirc door is fully open (i.e. full fresh air flow from outside).  This is all in the shop manual.  (In today's modern car A/C, they offer full recirc.).

 

Personally, I like having full recirc on my A/C all the time, instead of cooling down the hot, humid outside air in Houston.  So that is why I modified my system to be open for heat (all fresh air) and closed for A/C (full recirc) by having no vacuum applied to either diaphragm (or either port of a 2-port diaphragm, like you use on the plenum on the firewall under the hood).  I don't use the partial open setting at all.

 

The spring pulls the recirc door closed (full recirc -- no outside air) if no vacuum is on a diaphragm under the fan.  Better than what Buick did for cooling.  BTW, they were concerned about carbon monoxide poisoning.  That's why they wanted to bring in the fresh air all the time.  No cat converter on these cars, lots of CO.  Be careful!

 

 

 

 

 

Jim,

  It has been my experience working on many, many cars and truck AC systems that it is common for the manufacturer to allow for a partial fresh air intake even in recirc mode. The reason is full/complete recirc  has the potential to make the conditioned air TOO dry, especially on long and extended trips. A small volume of outside air is enough to add a little humidity to the recirculated cabin air and ultimately output air. The symptoms of AC air that is too dry are an irritated throat/respiratory system and personally I have noticed it has a negative effect on my eyes.

Regarding an "air in" door...if the door does not exist it is possible and very often the case with a malfunctioning door that firewall/plenum pressure while the vehicle is at speed can pressurize and force unwanted air flow from the HVAC registers. Providing an "air in" door prevents this phenomenon from occurring. There are instances of this issue in factory service bulletins over the years.

  Tom

[Turbinator]

17 hours ago, Jim Cannon said:

 

No, Bob... if you have ice on the line, leave it alone.  It is normal, especially in a humid place.

 

If you are running R-134a and you do not have ice, if the outlet temperature of the air is not too cold, lower the suction line pressure a few psi.  You don't need to change anything, you are good.

Jim, in the AC repair/replacement I stayed with your philosophy of original design by staying with rebuilt STV from Old Air and Actuator and the R12. I have a full time mechanic friend helping me and showing me how to put the vacuum system back together. My mechanic uses the shop manual a lot and requires the best parts I can afford. I won't argue. The forum points me in the right direction with good guidance,

thank you

RRB

[KongaMan]

45 minutes ago, Red Riviera Bob said:

Jim, in the AC repair/replacement I stayed with your philosophy of original design by staying with rebuilt STV from Old Air and Actuator and the R12.

 

Wise decision.  While one might rationalize a switch to R134A, there's no doubt that you'll get better performance with R12.  Replacing the STV with a cycling switch is just half-assery.

[60FlatTop]

Wow! There is a lot in this thread. I just looked at it for the first time today. It looked like it just related to the damper diaphragms. I guess I will go back and read it. Most of my life I have earned my living operating large refrigeration equipment. I think I owned my first operating AC car in 2000 or 2001. My '64 Riviera has never had a compressor on it, but I do remember repairing the cracked door actuator back around 1980 for cosmetic reasons.

As I was just reading through I was trying to remember if I have ever driven the car with the windows rolled up.

 

Just in case this sounds strange, take a look:

 

I live at the bottom of that blue arrow. A warm day around here means flannel shirt weather. A reason for the windows open when it is "warm". Also a reason why I haven't fished the chrome window divider strip out of the quarter panel.

 

On the technical side, 134A is about 15% less efficient than R-12. Off the top of my head 134A has a latent heat of 58 BTU/Lb and 12 is 70 or so. Automotive compressors are positive displacement so they need to cycle or have an evaporator pressure regulation device of some sort. Engine driven at variable speeds brings another control function along with the varying load.

 

If anyone is doing a restoration and finds some NOS hoses that they use in a 134A conversion they will leak the charge overnight. Used ones won't. The coat of refrigeration oil from use will seal them. If you go new you have to use triple wall hose.

 

Fin spacing and the presence of a defrost cycle in a refrigeration system are an indicator of operating temperature. Wide fin spacing indicates allowance for ice, operating below freezing. A defrost cycle anticipate ice formation. Neither applies to cars. A minimum coil temperature should be about 38 degrees for proper cooling and dehumidification. With a 5 degree approach that would exit the vents at 42 or 43. Mixed with the air in the car at about 70 degrees you end up at about 55% RH. That is pretty comfortable. If spending time in an air conditioned car is uncomfortable something is off and the best first step is to plot the vent temperature and cabin temperature on a psychrometric chart. Just figure the exiting air saturated at 100% unless the numbers don't work.

 

Today is a warm day. We just moved out of the 70's, temperaturewise. Lunch in the convertible!

Bernie

[Turbinator]

Gents, we always want the best job possible so our old cars continue to perform the way they were intended to work.  I'm the first to choose the best solution.  Example: when my manual control water valve stopped working there were no more manual control valves to be had. A named expert from the ROA recommended using a vacuum water control valve and gave instructions on how to install on my 63 Riv. I followed the experts instructions. I found the vacuum control valve a fine choice and a good solution. 

On the other hand I fixed a 63 Riv wheel cover that was rusted out pretty good with JB weld. Painted the inside of the wheel cover with POR 15. The wheel cover is on my car to this day and works good. ( now I have spare parts to rebuild the wheel cover). Now, the JB weld was half baked b/c there were other mechanical solutions  that were much better, but I didn't know about rebuilding hubcaps.

 

in 83 I lost a significant installation of new electronic accounting systems that was interfaced to mechanical meters. I didn't know about RFI then that caused the system to not work right. I took back the system and lost the installation. The same accounting system was installed in another state and the technician wrapped aluminum foil around the cable leads and the installation was successful. Wrapping aluminum foil around cables to shield from RFI? Half assed to say the least, but the installation was a success. I've seen some right comical half baked repairs that got the job done, because there were no other choices.

RRB

[KongaMan]

On the assumption that you're responding to my comment about half-assery, I'll explain...

 

It's important to understand what the STV does and how it works.  In a nutshell, it varies the evaporator pressure, which, in turn, changes the temperature of the outlet air.  It is controlled by the vacuum modulator attached to the temperature control on the dash: the less vacuum at the valve, the lower the evaporator pressure and the lower the outlet air temperature.  Push the control all the way down, the vacuum to the valve drops to 0, the evaporator pressure drops, the air gets colder.  Slide the control back up, the vacuum to the valve rises, the evaporator pressure rises, the air gets warmer.

 

If the STV is replaced by a cycling switch, it's entirely different.  In that setup, the evaporator pressure is always at its lowest setting; the outlet temperature is always as cold as it will go.  The system is cycled according to feedback from a new temperature sensor on the evaporator.  This is how it works: the system runs fullout until the sensor says it's too cold, then the compressor shuts off.  When the sensor indicates it has warmed up, the compressor kicks on again. And so on.  What you may have noticed is that you have no control over this: your temperature control is inoperative.  You cannot change the temperature at the outlets.  If you want it a little bit warmer (e.g.dehumidifiing on a cool, foggy evening ), you're SOL.

 

IOW, you now have a cruder, less capable system.  IMHO, it's far better to rebuild your STV (if that was problem) and keep the original functionality than to replace it with inferior components.

 

NB: IIRC, the STV on the Riviera works differently from the STV used on other contemporary full-size Buicks. For those cars, higher vacuum at the valve lowers the evaporator pressure.  This is why the the Riviera AC can be such a PITA to fix; it has some unique parts.

Edited August 18, 2017 by KongaMan (see edit history)

[Turbinator]

Bernie, I've heard you have three seasons in that part of the country: July, August, and winter. I swam in Lake George a long time ago and I must say the water cold in August. 

RRB

[60FlatTop]

It is interesting that the nearest city on my map is in another country. Cornell University has a deep water cooling system in Seneca Lake where the water is always 35 degrees.

[60FlatTop]

58 minutes ago, Red Riviera Bob said:

because there were no other choices.

RRB

 

Should end "within the paradigm of the application. That is the dangerous part, a little knowledge.

 

In 1983 an electronic accounting application would have lived up to the definition of college level learning, the conceptual use of knowledge from one field to another. I added conceptual from my own 50 years of experience. Details are often overlooked in exchange for commitment.

 

I started using communication circuits in 1974 with token ring technology and some fiber optics. Unshielded cable was fine for binary points. And they were the majority. The cost was about $500 per point compared to analog points at about $2,000 per. Analog used current loops with resistance sensors and were always installed with shielded (tin foil) wire. There just weren't many and may not have been obvious to the application investigator.

 

On the AC, follow the book and make it as original as possible. Back to my personal  experience, my greatest successes have come from recognizing and removing "improvements".