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#1 |
Senior Member
Join Date: Feb 2006
Location: Las Vegas
Posts: 1,378
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When this valve in the cowl panel closes, does the inside kick panel vent opens? Thanks, Luis.
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1972 Chevrolet Blazer 4x4 (Almost done stay tuned) 1970 Chevrolet Pickup Longhorn CST/20 (SOLD) |
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#2 |
454 MAKES IT ROAR
Join Date: Jan 2008
Location: Essex, U.K
Posts: 2,701
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Re: A/C air shut off valve
Wow spooky! I was going to post this question as well, I noticed this the other day when I fitted my new vacuum valve under the hood and as you say the door under the cowl closes and the vent kick panel opens....it can't be right, anyone know if this is correct?
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Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger Last edited by eightbanger; 03-20-2008 at 03:18 AM. |
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#3 |
member #16
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Location: Yuba City Ca.
Posts: 3,618
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Re: A/C air shut off valve
Just a guess, but wouldn't that be changing from outside air to inside air? It has to get air from somewhere.
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john http://67-72chevytrucks.com/vboard/showgroups.php board vendors ![]() http://www.flickr.com/photos/1745471...7602865984234/ |
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#4 |
454 MAKES IT ROAR
Join Date: Jan 2008
Location: Essex, U.K
Posts: 2,701
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Re: A/C air shut off valve
Yes the lever on the heater control is set to inside when this happens but when I move the selector lever to outside air the kick panel vent closes again but the vent door under the cowl still remains shut, and all my vacuum valves have been replaced so they are working fine.
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Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger |
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#5 |
Senior Member
Join Date: Jul 2001
Location: Muskegon,MI,USA
Posts: 6,026
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Re: A/C air shut off valve
For the coldest AC setting the vent door opens, the water valve closes, and the air door closes on the 70-72 trucks with the two port vacuum switch. Here is a schematic of the two port vacuum switch that I believe you have on your truck. (I can post the three port switch if for some reason your truck has one).
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1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC |
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#6 |
Registered User
Join Date: Mar 2008
Location: SoCal USA
Posts: 5
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Re: A/C air shut off valve
Where exactly is the control head vacuum switch (as shown on daigram) located in the truck? Also would a problem with that switch be responsible for allowing outside air to flow in through the A/C vents when moving, but not when stopped, even if the heater/A/C is switched off?
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#7 | |
454 MAKES IT ROAR
Join Date: Jan 2008
Location: Essex, U.K
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Re: A/C air shut off valve
Quote:
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Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger Last edited by eightbanger; 03-20-2008 at 04:16 AM. |
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#8 | |
454 MAKES IT ROAR
Join Date: Jan 2008
Location: Essex, U.K
Posts: 2,701
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Re: A/C air shut off valve
Quote:
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Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger |
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#9 |
Senior Member
Join Date: Jul 2001
Location: Muskegon,MI,USA
Posts: 6,026
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Re: A/C air shut off valve
eightbanger,
There should be a spring on the door to open it up when the vacuum is off. Here is a pic of the spring, (the upper end of the spring is hooked to the wrong hole in the picture).
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1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC |
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#10 |
Gettin By on Gettin By
Join Date: Jan 2008
Location: Cedar Creek, Tx
Posts: 1,033
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Re: A/C air shut off valve
Think of it like a Max setting, or recirculate. It just shuts off all out side air and recirculates then air in the cab.
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#11 | |
454 MAKES IT ROAR
Join Date: Jan 2008
Location: Essex, U.K
Posts: 2,701
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![]() Quote:
Thanks everyone.
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Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger |
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#12 |
Registered User
Join Date: Feb 2008
Location: Jackson, TN
Posts: 99
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Re: A/C air shut off valve
I too am missing this spring. do you know anyone who sells this spring? I'm sure I could use a generic spring if I knew the length and pull strength of the spring. Any idea? I'm considering modifying with a 12V door lock actuator to replace the vacuum.
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#13 |
Registered User
Join Date: Mar 2014
Location: Gilbert, AZ
Posts: 8
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Re: A/C air shut off valve
I am looking for a "Control head Vacuum Switch" that is missing on the back of my heater control. Cany anyone help me with a part number or resource to purchase one? Thanks, Bob
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#14 |
Senior Member
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Location: alb, nm
Posts: 413
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Re: A/C air shut off valve
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#15 |
Registered User
Join Date: Sep 2013
Location: Vacaville CA
Posts: 490
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Re: A/C air shut off valve
I don't have that spring, either! NEVER HEARD OF IT!! Thanks so much!
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#16 |
Senior Member
![]() Join Date: May 2010
Location: Wisconsin & Arizona
Posts: 4,844
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Re: A/C air shut off valve
Here's a picture of an original spring. It is very "stout". They are almost always missing due to their location and rust. They are not reproduced as far as I know.
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#17 |
Senior Member
![]() Join Date: May 2003
Location: Sandown, NH
Posts: 2,819
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Re: A/C air shut off valve
Go to your local hardware store, they usually have an assortment of springs, I found one similar to the one Firstowner posted. Also note the one in the first picture, is hooked to the wrong hole in the cowl. It should be in the hole to the right that's a little further away from the windshield. At least that's what I was told.
Gary
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Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859 |
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#18 | |
Senior Member
![]() Join Date: May 2010
Location: Wisconsin & Arizona
Posts: 4,844
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Re: A/C air shut off valve
Quote:
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#19 |
Registered User
Join Date: Apr 2011
Location: Klein Texas
Posts: 3,852
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Re: A/C air shut off valve
Thanks for posting the pics. I went and checked and my spring is missing. Off the hardware store I go
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My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe |
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#20 |
Registered User
Join Date: Apr 2014
Location: Southern California
Posts: 200
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Re: A/C air shut off valve
subscribed
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#21 |
Registered User
Join Date: Aug 2011
Location: Queen Creek, AZ
Posts: 39
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Re: A/C air shut off valve
Great info. Thanks!
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#22 |
Registered User
Join Date: Jul 2011
Location: El Campo, Tx
Posts: 1,246
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Re: A/C air shut off valve
I like this thread. It is very informative. Subscribed for future reference
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72 Chevy blue LWB, 99% original Oklahoma truck, 28,000 miles 72 Chevy SWB: http://67-72chevytrucks.com/vboard/s...d.php?t=486626 (Attempt/Mistake #2) 2003 Harley Davidson Dyna Superglide with 2007 Street Bob front end 2000 Ford F350 Powerstroke 4WD CCLB, 310,000 miles running great (STOLEN St. Patricks Day 2014 AND NEVER RECOVERED) 2002 Ford F250 Powerstroke 4WD CCLB (To replace stolen one) Hook em Horns!!! |
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#23 |
Registered User
Join Date: Mar 2011
Location: Brandon,Iowa
Posts: 391
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Re: A/C air shut off valve
I learned something new today about the presence of this spring and the fact that I don't have one ! Thank You for the info !!!!
Tom |
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#24 |
Old member
Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
Posts: 19,936
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If your not a puriest the best mod you can do is close off that cowl vent completely! Seal it up tight and never close the passenger side kick panel vent again.
I'm not joking either. Your AC will be cooler and you want have all these problems with it anymore.One of the best mods I ever did, ![]()
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1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 ![]() Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs. |
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#25 |
Registered User
Join Date: Jun 2014
Location: Glendale, Arizna
Posts: 1,642
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Re: A/C air shut off valve
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