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7/21/08 1:29pm - Original Message: 'Vacuum loss affecting AC vents?'
terntes
Former Member
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Little Rock, AR - USA

Vette(s):
1982 Collector Edition

Joined: 7/10/2007
Posts: 116
  I'm still fighting my vacuum drop, which lets my AC actuator / door open or close, whichever; my air flow drops under acceleration then returns under normal cruising conditions. Is there a main vacuum chamber somewhere that may be the culprit. All the vacuum lines look ok, as far as I can tell. I cannot get behind the dash (yet) and the control under the console appears to be functioning properly. I have also had trouble with my headlights not opening easily or at all. Is there a complete vacuum diagram anywhere? I have the complete assy. and Haynes and Chilton for my '82, but they are not good.
terntes
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7/21/08 1:51pm - Reply: 'Vacuum loss affecting AC vents?'
Aaron1976
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Vancouver, WA - USA

Vette(s):
1976 Corvette Stingray L-48 Automatic Black

Joined: 11/17/2007
Posts: 830
Try www.corvette-101.com they have vacuum trouble shooting info and some diagrams. The rest of the gang here will also help you out.Big%20smile

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7/21/08 2:56pm - Reply: 'Vacuum loss affecting AC vents?'
Ron 78 Lifetime Member
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BINGHAMTON, NY - USA

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Joined: 7/19/2003
Posts: 3805
On my 78,the main vacuum canister is part of the frame the big cylindrical tube in front of the radiator,I don't know if they stuck with that change from the "coffee can" up to 82 or if they changed back to the coffe can version on yoursConfused

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7/21/08 6:04pm - Reply: 'Vacuum loss affecting AC vents?'
terntes
Former Member
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Little Rock, AR - USA

Vette(s):
1982 Collector Edition

Joined: 7/10/2007
Posts: 116
My car does have a coffee can in front, I thought it was specifically for the headlight system. It looks in good condition and all the lines look good and tight. I'll do more research.
terntes
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7/21/08 7:39pm - Reply: 'Vacuum loss affecting AC vents?'
crossfire1982
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Cramerton, NC - USA

Vette(s):
black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion

Joined: 8/22/2006
Posts: 1094

There is a check valve in the headlight vacuum line which goes to the headlight system, check this valve.  It is covered at the link that Aaron posted.  check the vacuum lines where they connect to the two headlight vacuum relays, hoses tend to loose their elasticity with age and may not seal well there.  when checking the vacuum can, check the upper end where water can collect and rust out the seams, mine had lots of small leaks where I couldnt see them.    There is a plastic "T" up near the brake booster that sends one line through the firewall to the heater controls, check this "T", mine was cracked just enough to keep my vacuum actuators from working the air control doors.  I believe there is a vacuum line which goes to the gasoline vapor recovery (charcoal) canister. All of these lines which leak may add up and steal the vacuum you need to operate other "stuff".



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7/22/08 4:11am - Reply: 'Vacuum loss affecting AC vents?'
terntes
Former Member
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Little Rock, AR - USA

Vette(s):
1982 Collector Edition

Joined: 7/10/2007
Posts: 116
  Thanks for the ideas! I've seen all these items and visually checked them and physically somewhat. My check valve leaks back a little ( I did a blowtest ), my filter has been altered to allow stronger vacuum, someone poked a hole through the filter. The hoses all look good but there is probably small leakage everywhere. I wish there was one vacuum diagram for the entire system instead of one for the fuel system, one for the engine, one for the headlights, one for the climate control, etc., maybe we need a forum just for vacuum, it is my biggest headache.
terntes
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7/22/08 6:04pm - Reply: 'Vacuum loss affecting AC vents?'
california68 Lifetime Member
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Yorba Linda, CA - USA

Vette(s):
1968 convertible, small block, auto, pw, pb, ps, air, 3rd owner CA black plate

Joined: 3/19/2008
Posts: 53
Try Doc Rebuild....  http://www.docrebuild.com/
He is a master at the vacuum and has all the diagrams too.


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7/22/08 10:54pm - Reply: 'Vacuum loss affecting AC vents?'
my7t1 Lifetime Member
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Dorr, MI - USA

Vette(s):
71 Colonnade Hardtop Coupe Torch Red with black interior originally L48 built to push around 360hp

Joined: 8/21/2002
Posts: 2580
Here's another site I found very useful.

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7/23/08 12:47pm - Reply: 'Vacuum loss affecting AC vents?'
terntes
Former Member
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Little Rock, AR - USA

Vette(s):
1982 Collector Edition

Joined: 7/10/2007
Posts: 116
  Thanks, I hope he is good, I ordered a complete kit, plus diagram and catalog yesterday. I'm glad he is recommended.
terntes
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7/23/08 12:49pm - Reply: 'Vacuum loss affecting AC vents?'
terntes
Former Member
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Little Rock, AR - USA

Vette(s):
1982 Collector Edition

Joined: 7/10/2007
Posts: 116
  This diagram differs from mine, no wiper doors and there is a cannister up front where the headlights are. I don't know if it is the main tank or where the fuel vacuum tank is? I hope Doc Rebuild can tell me.
terntes.
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