missing vacuum hose

Old April 25th, 2018, 07:35 PM
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missing vacuum hose

1969 cutlass s convert, v8/4bbl w/ a/c, pb
going over the engine, i notice, what i assume is a vaccum can, on the driver side tucked under fender by firewall. There is a vacuum line going off can an into firewall to under the dash. The other port on the can has nothing going to it. I assume a vacuum line from the engine goes to it. what is this for. I have looked in my manual and it appears something to do with heating/cooling?
thanks.
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Old April 25th, 2018, 07:37 PM
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Do you have a trunk release button in the glove box?
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Old April 25th, 2018, 07:47 PM
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i do, it doesnt work and ive never really looked into it. i figured it was electric operated.
thanks
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Old April 26th, 2018, 07:28 AM
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The A/C flapper doors under the dash are vacuum actuated. There is a vacuum can on the firewall to act as a reservoir for this system. Normally, there is sufficient manifold vacuum to operate these actuators, but if you step on the gas, manifold vacuum drops briefly. The reservoir serves to maintain the function of the vacuum actuators during this period of low manifold vacuum. If the can is not connected, you may just not have noticed the temporary drop-out of vacuum under acceleration.

If you have a vacuum trunk release, there would have been a separate vacuum canister for that system. That canister is intended to retain vacuum to allow you to operate the trunk release after the engine is turned off.
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Old April 26th, 2018, 08:03 AM
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It is for the trunk release, that's where my can is. It needs to be tee'ed into the main vacuum to work.
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