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Vacuum hoses!!! Ahhhh!!!

49K views 77 replies 49 participants last post by  djaws 
#1 ·
Okay, does anyone have a diagram for a 1970 Chevelle A/C vacuum hose lines?

Also, how exactly does the vacuum canister mounted on the box in the engine compartment work? How does the flow of vacuum work?

Just trying to get a good understanding before I put everything back in my car.

Thanks,
Ray C
 
#2 ·
The vacuum canister has two ports. The larger port is the vacuum source and connects to the intake manifold via a hose obviously. The smaller port connects to a hose which goes thru the firewall. That hose is connected to port #6 of the main vacuum function switch and port #1 of the temperature vac. switch . Check your email I sent you two documents which should explain everything.
 
#77 ·
Does anyone have the A/C vacuum hose diagram for 1972 years? Need to know what the change is on the temperature selector vacuum port #2 (of three ports) since 1972 did not use the coolant heater hose control valve. Anyone know what the changes are if there is no diagram? I searched high and low on Google...no results for 1972.
 
#14 ·
I am assuming you are saying that you do not have factory ac, correct? Just heat, right? I havent worked on anything but factory AC on 70-72 chevelles. I havent messed with a non-ac car.

Take your dash pad off and have a look bro. Do you have vacuum lines going to the control assembly? If so, you need to follow them and see where they go. I bet you have one line that goes to the passenger inner fender and hooks up to a water valve. That should turn the flow of coolant/antifreeze on or off to your heater core.

I Bet wherever that vacuum line comes through the firewall is another vacuum line. That probably needs to be hooked up to the intake or a vacuum canister. I would say that a heater only system should be very simple to troubleshoot. the cable only opens and closes a door that mixes hot air and outside air to get the different temperature of air coming into the car.
 
#15 ·
Does anyone have the heater AC vacuum diagram for a 72 chevelle. Does anyone know what vacuum hose controls the heater control valve on a 72 chevelle. I have the diagram for a 1970 vacuum system but it shows a white hose that comes off the heater control. The heater control that I am using for a 72 chevelle does not have the white one as far as I can tell. Thanks in advance for the help!
 
#17 ·
:thumbsup:Could i get a copy of that also? I have a friend that i'm working on his 70.wren1999@verizon.net Thanks in advance.
 
#29 ·
Years ago I had a '69 Ford LTD with the vacuum-operated headlight covers. Was at an Air Force base, and the base library had dozens of repair manuals including one that had vacuum diagrams just like wiring diagrams for all kinds of GM, Ford, and Chrysler cars. Maybe people don't use libraries any more? Heck, maybe they don't even exist...
 
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