C2 A/C vac control question...
Thread Starter
Burning Brakes
Joined: May 2011
Posts: 760
Likes: 104
From: Lewiston NY
2020 C8 of the Year Finalist - Modified
St. Jude Donor '12-'13-'14,'17, '20-'21
C2 A/C vac control question...
Is the vacuum control unit under the dash for the a/c shut simply destined to leak? I am on my 3rd one now. The original leaked, likely from age. The first replacement leaked almost out of the gate and the third one lasted a few months.
The leak isn't great, but it is enough that I can hear it at idle hissing away under there and it bugs me.
The leak isn't great, but it is enough that I can hear it at idle hissing away under there and it bugs me.
Instructor
Joined: Sep 2011
Posts: 149
Likes: 1
From: Troutman North Carolina
That's the shutoff valve for the heater control valve. I put a new brass one in mine from LIC, and have no problems for 2 years so far. "knock on wood"
Make sure that you route the vacuum lines very carefully, If not, they may contact the mechanical linkage and be torn, cut or knocked loose from the linkage movement.
There are clips that hold them to the case away from the linkage.
Make sure that you route the vacuum lines very carefully, If not, they may contact the mechanical linkage and be torn, cut or knocked loose from the linkage movement.
There are clips that hold them to the case away from the linkage.
Racer
Joined: Aug 2010
Posts: 461
Likes: 5
From: San Clemente California
That's the shutoff valve for the heater control valve. I put a new brass one in mine from LIC, and have no problems for 2 years so far. "knock on wood"
Make sure that you route the vacuum lines very carefully, If not, they may contact the mechanical linkage and be torn, cut or knocked loose from the linkage movement.
There are clips that hold them to the case away from the linkage.
Make sure that you route the vacuum lines very carefully, If not, they may contact the mechanical linkage and be torn, cut or knocked loose from the linkage movement.
There are clips that hold them to the case away from the linkage.
Tom
Thread Starter
Burning Brakes
Joined: May 2011
Posts: 760
Likes: 104
From: Lewiston NY
2020 C8 of the Year Finalist - Modified
St. Jude Donor '12-'13-'14,'17, '20-'21
Not sure we are talking the same piece. This is the piece here. Didnt see one on lic site but I saw a different looking brass shut off valve
http://corvetteparts.com/item/switch...yle-1963-1967/
http://corvetteparts.com/item/switch...yle-1963-1967/
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
There is actually a built in leak, but I dont think it comes into play except to release the vacuum to the actuator. I have never noticed any sound coming from it.
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Thread Starter
Burning Brakes
Joined: May 2011
Posts: 760
Likes: 104
From: Lewiston NY
2020 C8 of the Year Finalist - Modified
St. Jude Donor '12-'13-'14,'17, '20-'21
Maybe a little penetrating oil to soften up the seal?
Thread Starter
Burning Brakes
Joined: May 2011
Posts: 760
Likes: 104
From: Lewiston NY
2020 C8 of the Year Finalist - Modified
St. Jude Donor '12-'13-'14,'17, '20-'21
I have a clear low-grade hiss. When I wiggle the actuator the pitch changes so I assume it is a seal there.
Instructor
Joined: Sep 2011
Posts: 149
Likes: 1
From: Troutman North Carolina
That's the heater valve shut off switch. Were all of the leaking ones from the same vendor ? Maybe try another vendor, they might have a different part supplier. Worth a try.
Or just turn the radio up. He He !
Or just turn the radio up. He He !
Race Director
Joined: Apr 2005
Posts: 11,284
Likes: 2,146
From: Bowling Green, Kentucky
One of our forum guys took one apart and documented the process. It will be in the archives. I will try to find it and post the link.
I believe that LICS had this valve reproduced, so all the valves out there should have come from them. But perhaps some revisions were done on later batches of the switch to correct issues. No one else that I know has reported this issue from a recent LICS switch. You could remove the switch and then use a Mighty-Vac or something similar to check it out on the bench. The issue may be a split hose...............
Larry
EDIT: http://forums.corvetteforum.com/c1-a...uum-valve.html
Last edited by Powershift; Dec 11, 2013 at 08:34 AM.
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
Is the vacuum control unit under the dash for the a/c shut simply destined to leak? I am on my 3rd one now. The original leaked, likely from age. The first replacement leaked almost out of the gate and the third one lasted a few months.
The leak isn't great, but it is enough that I can hear it at idle hissing away under there and it bugs me.
The leak isn't great, but it is enough that I can hear it at idle hissing away under there and it bugs me.
Instructor
Joined: Nov 2010
Posts: 218
Likes: 2
From: Harrisburg Penna
Be sure to check the mounting bracket on the repro valves ! They appear to be attached with "super glue". Mine was loose and would have broken completely loose. I used a fine file to dress up the brass and good old JB Weld. I was told by the vendor that they are all provided by LIC.
Racer
Joined: Aug 2010
Posts: 461
Likes: 5
From: San Clemente California
Be sure to check the mounting bracket on the repro valves ! They appear to be attached with "super glue". Mine was loose and would have broken completely loose. I used a fine file to dress up the brass and good old JB Weld. I was told by the vendor that they are all provided by LIC.
Tom
Instructor
Joined: Nov 2010
Posts: 218
Likes: 2
From: Harrisburg Penna
You are correct. But as of 10/2013 LIC no longer makes the vacuum switch for late 64-67 cars with A/C and won't be in the future. The early one for 63-early 64 has one small and one larger diameter vacuum hose nipple. The later one has two small dia nipples. And they are built with a designed vacuum leak according to the Restorer article I read sometime back. Mine has it and works perfectly. When the engine is running I can't hear it crawling up under the glovebox. I must've lucked out.
Tom
Tom
Racer
Joined: Aug 2010
Posts: 461
Likes: 5
From: San Clemente California
Tom
Thread Starter
Burning Brakes
Joined: May 2011
Posts: 760
Likes: 104
From: Lewiston NY
2020 C8 of the Year Finalist - Modified
St. Jude Donor '12-'13-'14,'17, '20-'21
never thought to test it with a vacuum tester to locate problem. i'll do that.
also, the switch itself works shutting off the heater and bringing on the AC, it just hisses and that bugs me. It thought I capped the end, maybe not that well. I will also check for the other issues and look at a later model valve. thanks for all the input.
also, the switch itself works shutting off the heater and bringing on the AC, it just hisses and that bugs me. It thought I capped the end, maybe not that well. I will also check for the other issues and look at a later model valve. thanks for all the input.
Thread Starter
Burning Brakes
Joined: May 2011
Posts: 760
Likes: 104
From: Lewiston NY
2020 C8 of the Year Finalist - Modified
St. Jude Donor '12-'13-'14,'17, '20-'21
Out and tested on the bench. I dipped either end in a glass of water and put the vac tester on it. the rear of the switch did not suck in water, the front or button side drew in water like a straw.
I'll buy another one and keep the receipt.
I'll buy another one and keep the receipt.