A/C-Heat rotary vacuum switch

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A/C-Heat rotary vacuum switch

Postby 74_Vega_GT » Wed Apr 28, 2021 10:59 pm

~ Can someone please post the link to the pics of the dissasembly by Zeke of this component? Search turned up nothing. Is this part still available? This would be for the 77 Sunbird with the Bi-Level setting and the colored temp area. This component is keeping my vent door actuators from working I suspect. I checked National Parts Depot for a Camaro one, but it did not look the same.
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1974 Chevy Vega GT Hatchback
1982 Chevy S-10 longbed 2.8v6 A/C
2005 Chrysler Crossfire SRT-6 Coupe,Black
2005 Chrysler Crossfire SRT-6 Coupe,Silver Sapphire Blue
2005 Chrysler Crossfire Roadster N.A., Silver Sapphire Blue
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Re: A/C-Heat rotary vacuum switch

Postby classic_cruiser » Fri Apr 30, 2021 7:13 pm

I went looking but couldn't find the article. But the vacuum control is not hard to take apart - if I recall correctly the vacuum manifold is only held onto the selector control with two of those one-way push clips, but they can be coaxed off. There should be three vacuum lines, one that that runs to the upper air door control, one that runs to the lower heat door and one that goes to the recirc door if I remember right. Usually its the vacuum actuators that start to leak, have you tried to test and make sure they hold a vacuum?
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Re: A/C-Heat rotary vacuum switch

Postby 74_Vega_GT » Sun May 02, 2021 9:25 am

~ Thanks for the reply...This vacuum "distributor" has 6 hoses coming off of it, one is the supply. The body is aluminum and has 2 halves and is reveted together and has a clip on the underside, has 2 screw holes.
~ I sprayed it good with PB blaster and attempted to drill the rivet and gave up, then peened the rivet to tighten the two body halves. It turns smoothly, however, I think I remember reading that the Corvette uses the same one. I went to Eklers dot com and found what appears to be the correct component, ordered it, should be here by Tuesday.
~ Bought ...another tool...a hand held vacuum tester brake bleeder tool. I connected it to the rubber hose octopus, one hose at a time and did observe the main door move open...then connected to a different hose and observed the main center door close. I observed the air change ( blower ON ) from the defrost vents to the AC vents. I feel like the diaphrams are OK.
~ If this part for the Corvette turns out to be the correct part...(25.00) I will post either my sucess or failure.....peace
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1974 Chevy Vega GT Hatchback
1982 Chevy S-10 longbed 2.8v6 A/C
2005 Chrysler Crossfire SRT-6 Coupe,Black
2005 Chrysler Crossfire SRT-6 Coupe,Silver Sapphire Blue
2005 Chrysler Crossfire Roadster N.A., Silver Sapphire Blue
2005 Chrysler Crossfire Roadster N.A., Aero-Blue
2008 Dodge Ram Longbed, Brilliant Crystal Pearl Black
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Re: A/C-Heat rotary vacuum switch

Postby TTait » Fri May 07, 2021 5:28 am

I can get you rebuild instructions for a similar switch for Delorean if it helps.

Among other tips when rebuilding this type of switch, you will find a rubber gasket in the middle with a pattern in it that looks like a maze through which air can travel in certain positions. In general, a rebuild involves disassembly of the switch - make sure to take reference photos first - and watch out for spring loaded ball bearings. Often the only part you need to replace is this molded rubber gasket. When installing the new one its advisable to use a very thin coating of petroleum jelly on it. I guess if you can't get a new one, disassembling it and lightly lubing it with petroleum jelly might help.

Watch out again for losing small parts like springs or ball bearings that can be used in some assemblies to create the detents you might feel when rotating the knob. Because they are spring loaded they could go some distance away if they got away from you.

LMK if instructions for a similar but not identical unit would be helpful.

Tom
On my third H Body - 1975 Monza 2+2 4.3L Orange/Black (Current State: Running great - needs the AC finished before summer hits hard)
76 Monza 2+2 L4 (1982-1987)
77 Starfire V6 (1987-1987)
82 Delorean - Universal Raffle Car (2005-2013)
81 Delorean 2009 - Present
17 Chevy Bolt 2017- Sold back to GM for almost a full refund
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Re: A/C-Heat rotary vacuum switch

Postby 74_Vega_GT » Fri May 07, 2021 7:49 am

~ I was mistaken abbout the number of hoses coming off of the vacuum switch, there are 5 hoses not 6.
~ The Corvette part is NOT the same . It does have nine nipples for the hoses, the nipples are in the correct configuration. The bottom half of the switch where the "ears" are for the screw holes is oriented differently. It might have worked in a pinch, but I found NOS OEM correct one up on eeee-bay, it's on the way.
>I Love the H-Body forum and am grateful for it and all its members contributions, disclaimer below is directed at search engines.
> Photographs posted by this user (74_Vega_GT) are the sole property of this poster. Any use without express written permission is prohibited.
1974 Chevy Vega GT Hatchback
1982 Chevy S-10 longbed 2.8v6 A/C
2005 Chrysler Crossfire SRT-6 Coupe,Black
2005 Chrysler Crossfire SRT-6 Coupe,Silver Sapphire Blue
2005 Chrysler Crossfire Roadster N.A., Silver Sapphire Blue
2005 Chrysler Crossfire Roadster N.A., Aero-Blue
2008 Dodge Ram Longbed, Brilliant Crystal Pearl Black
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Re: A/C-Heat rotary vacuum switch

Postby Monza Harry » Fri May 07, 2021 7:18 pm

74_Vega_GT remember that the Vette may have been available with Climate Control as well as A/C Climate Control in those years.I would expect "CC" to have Extra "we'll call it plumbing" [that is the unit with Temperature adjustment in degrees for those unfamiliar with 1970's (& 80's) GM vehicles. you could maybe check for Pic's if you are still curious. Harry
I'm not a hoarder I'm a preservationist 78 Monza Spyder (~Soon(ish +/- I guess) To Be 2+2 with Spoilers)
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1978 Chevrolet Monza 2+2

Re: A/C-Heat rotary vacuum switch

Postby 74_Vega_GT » Wed May 12, 2021 8:29 am

~ New part arrived.NOS..WD-40 loosened it up.
>I Love the H-Body forum and am grateful for it and all its members contributions, disclaimer below is directed at search engines.
> Photographs posted by this user (74_Vega_GT) are the sole property of this poster. Any use without express written permission is prohibited.
1974 Chevy Vega GT Hatchback
1982 Chevy S-10 longbed 2.8v6 A/C
2005 Chrysler Crossfire SRT-6 Coupe,Black
2005 Chrysler Crossfire SRT-6 Coupe,Silver Sapphire Blue
2005 Chrysler Crossfire Roadster N.A., Silver Sapphire Blue
2005 Chrysler Crossfire Roadster N.A., Aero-Blue
2008 Dodge Ram Longbed, Brilliant Crystal Pearl Black
74_Vega_GT
 
Posts: 455
Joined: Thu Jun 16, 2016 2:40 pm
Location: Central Florida

Re: A/C-Heat rotary vacuum switch

Postby TTait » Sun May 16, 2021 1:22 am

Not H body specific, but the general information still applies:

https://support.delorean.com/kb/a75/mod ... ilure.aspx

This shows what the wear component generally looks like:

https://support.delorean.com/kb/a75/mod ... ilure.aspx

I have rebuilt these for Delorean but I tossed the instruction sheet after completion. If anyone is attempting an H body rebuild and wants a copy of the Delorean instructions I'll request another copy and send you a PDF - just send me a PM and give me a day or two to get it done.

Unfortunately what tends to fail is formed rubber seal as pictured above that must hold vacuum while getting twisted around. The newest H bodies are now over 40 years old and it doesn't look like anyone is reproducing the gaskets so I expect this failure to become more and more common. sooner or later someone is going to disassemble their switch and do a 3D scan of the failed sculpted gasket. 3D printed reproductions in TPE or Silicon Elastomers are possible, a company called xometry will print them for example.
On my third H Body - 1975 Monza 2+2 4.3L Orange/Black (Current State: Running great - needs the AC finished before summer hits hard)
76 Monza 2+2 L4 (1982-1987)
77 Starfire V6 (1987-1987)
82 Delorean - Universal Raffle Car (2005-2013)
81 Delorean 2009 - Present
17 Chevy Bolt 2017- Sold back to GM for almost a full refund
22 Mustang Mach E on order
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Re: A/C-Heat rotary vacuum switch

Postby TTait » Sun May 16, 2021 11:42 pm

one more resource - not a H body but very similar:

https://www.youtube.com/watch?v=358qaLbb-Sc

Jimmy Kimmel is not in danger of losing his job to the host, but the process is laid out...
On my third H Body - 1975 Monza 2+2 4.3L Orange/Black (Current State: Running great - needs the AC finished before summer hits hard)
76 Monza 2+2 L4 (1982-1987)
77 Starfire V6 (1987-1987)
82 Delorean - Universal Raffle Car (2005-2013)
81 Delorean 2009 - Present
17 Chevy Bolt 2017- Sold back to GM for almost a full refund
22 Mustang Mach E on order
TTait
 
Posts: 73
Joined: Sat Feb 20, 2021 1:47 pm


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