1974 Lincoln Mark IV - Vacuum Issues


New LVC Member
Jul 21, 2021
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Please Help...
My son has a 1974 Lincoln Mark IV with 460/ $barrel Dual Exhaust.
We are dealing with a few issues, but I figured we will try to fix one at a time.

We have a vacuum issue.
When parked the headlight lids eventually will open exposing headlights.
Sometimes when shifting into reverse from drive and sometimes from Park to Drive the gear shifter will hiss and we will have to "jiggle" the shifter to get it to stop.
Also, when we turn the air conditioner on the fan blows and it pretends to work, but it only will blow through the defrost.
I have tried researching this, I have tried finding vacuum diagrams, but very little on diagrams and a plethora of suggestions on problem.

Could someone please help remedy this problem, thank you for your time and knowledge.
Jeff B

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