vacuum question

[streetdemon70]

On my 70 coupe the vacuum canister that is mounted in the fender well has a port for two hoses. I have the bottom port hooked up to something but i dont have anything hooked up to the top port? does anyone know what hooks up to the top port?
--A
TIA

 

[cgstang]

one is vacuum in and the other is vacuum out

 

[mudbilly]

what it's purpose is?????

i have been looking at that thing for 5 years and always wondered why it was there......

 

[Clark]

My 69 should be very similar to the 70 application, but the vacuum can is there like a storage tank so when you need vacuum to move the heater/AC controls it will provide a large amount of suction to move the actuators quickly. This is different from earlier models that had some cables.

 

[65ShelbyClone]

My 69 should be very similar to the 70 application, but the vacuum can is there like a storage tank so when you need vacuum to move the heater/AC controls it will provide a large amount of suction to move the actuators quickly. This is different from earlier models that had some cables.

Dang, so THATS what its for! I have a vac canister too, but had no idea what it was needed for. Thing is, mine only has one port .

 

[jbuening]

The vacuum cans are for A/C cars only. You should have a grommet with two small vacuum hoses coming through the firewall right above the passenger valve cover towards the top of the firewall. One goes to the heater hose valve that stops the coolant from going into the heater core and the other vacuum hose goes to the small port in the vacuum can. Then there should be a hose going from the large port on the vacuum can to the plastic vacuum tree on the firewall. You might want to test the vacuum can for leaks, cause mine had a hole rusted through it and would cause a vacuum leak and is the last thing that most people think of when diagnosing a vacuum leak. If you need pics please let me know. There is a J clip on the firewall that holds the two vacuum hoses when it runs along the firewall to the vacuum can.

 

[mudbilly]

The vacuum cans are for A/C cars only. You should have a grommet with two small vacuum hoses coming through the firewall right above the passenger valve cover towards the top of the firewall. One goes to the heater hose valve that stops the coolant from going into the heater core and the other vacuum hose goes to the small port in the vacuum can. Then there should be a hose going from the large port on the vacuum can to the plastic vacuum tree on the firewall. You might want to test the vacuum can for leaks, cause mine had a hole rusted through it and would cause a vacuum leak and is the last thing that most people think of when diagnosing a vacuum leak. If you need pics please let me know. There is a J clip on the firewall that holds the two vacuum hoses when it runs along the firewall to the vacuum can.

thankyou very much........

 

[jbuening]

One thing i did forget is that the vacuum can is also used for the tilt release for cars that came with tilt steering columns. Not sure what years it was used but i've heard of 67 and 68's having the cans for the tilt columns. Oh and you are welcome

 

[streetdemon70]

thanks turns out mine had a hole in it. got it fixed and the car runs much better. thinking since i got rid of my ac i can get rid of that vacuum can right? all i really need vacuum for is the brakes correct?
--A

 

[jbuening]

I wouldn't see why not. You would have a hole in the inner rear fender panel though. Do you have a stock cam or a beefier one? The more radical the cam the more vacuum the cam needs, thus the reason for aftermarket vacuum canisters that are sold by summitracing and jegs. As long as the hole was patched i wouldn't think it would hurt anything, if anything increase your vacuum a bit. If your A/C is gone and you don't have a tilt column (not sure if the tilt columns in 70 used the can) then its up to you to remove it.