The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 05-25-2007, 03:52 PM   #1
dan42
Registered User
 
dan42's Avatar
 
Join Date: Feb 2007
Location: Cali Central Coast
Posts: 5,191
Vacuum line from carb to?

There is a vacuum line that comes from the base of my carb and goes through the firewal and under the dash - does that assist the heater/ac controls? When I have it hooked up, I hear a hissing noise from under the dash, so I'm thinking I have a hole in the line under there somewhere.
__________________
'67 SWB Fleetside ZZ4/350/Tremec 5-speed/4link/Scott's IFS - and fun as heck! SOLD
Click here to support the board
Philippians 4: 6-7
dan42 is offline   Reply With Quote
Old 05-25-2007, 03:56 PM   #2
BurnoutNova
Registered User
 
BurnoutNova's Avatar
 
Join Date: Mar 2004
Location: CA
Posts: 2,057
Re: Vacuum line from carb to?

not certain, but if your truck has A/C there may be a vacuum reservior to actuate the mode doors, on gm cars atleast there like a 6" ball under the hood, but ive never seen where there at on the trucks
BurnoutNova is offline   Reply With Quote
Old 05-25-2007, 04:29 PM   #3
jhow66
Registered User
 
jhow66's Avatar
 
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
Re: Vacuum line from carb to?

Just follow the line and plug the end -no hiss -truck will run better (idle speed will slow down when you stop the leak)
__________________
56 Chevy Bel-Air 2dr. HT (purchased new)
71 Chevy Cheyenne SWB PU (502HO)
65 GMC short bed step--work in progress and my gofer
jhow66 is offline   Reply With Quote
Old 05-25-2007, 10:00 PM   #4
dwaite72lnghrn
Registered User
 
Join Date: Jun 2002
Location: central pa
Posts: 1,525
Re: Vacuum line from carb to?

Not sure what year you have but if it is factory air you will see a vacuum resovoir on the airconditioning housing above the passenger valve cover. One end runs to the "T" on the back of the intake manifold and the hose out the other side runs to the vacuum switch "top lever" of the heat/air controls. The vacuum switches can go bad and leak. attached is the vacuum diagram and a picture of a '72 vacuum canister.
Attached Images
  
__________________
72 longhorn c30 502BB/th400/fact air/4.11rear/ custom camper
72 bug(the better half's) under reconstruction
2009 HHR aqua blue
71 GMC k20 350/sm465
2009 Chevy hd3500 6.6 Victory Red crew cab dually
Dave & Jeanne
dwaite72lnghrn is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:33 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com