When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Can anyone idea this vacuum trunk release? I got it in a load of 70 to 72 parts but I know it’s not correct for that. I don’t know much about the earlier 68-ish vacuum trunk release was it in the body of the car or was it still in the lid of the trunk? Any help would be appreciated thanks Brandon
Jake, the latch is a spring loaded rotating thing. This can be pushed rotationally by the rod from the lock cylinder (that's what the rectangular hole is, it's for that shaft.) Usually, the lock cylinder immobilizes the latch, but vacuum release cars have a spring joint in them that allows them to rotate it open, but also allows something else to also rotate the back of the rod.
The vacuum release is a vacuum cylinder. When activated, vehicle vacuum causes air pressure inside the can to drop, and atmospheric pressure pushes a piston the diameter of the cylinder in. That piston has that rod sticking out, and it pulls on the latch lever. You can see it is slotted to allow the lock cylinder rod to manually do it as well.
In the engine bay, a vacuum line from an engine manifold source leads to an accessory vacuum can with a check ball. This accumulates vacuum, and, depending on the check ball and other leaks, will hold it for a good while. The outlet of the can goes to a switch in the glove box liner. Push the button and hold for a bit, and vacuum is pulled out to the cylinder in the trunk, and it opens the trunk. That switch, I think, when normally closed, also vents the line out the trunk to atmosphere to keep a vacuum from building up and randomly popping the lid.
Ideally, the vacuum should last a long time; several hours. Usually it works when the engine is on at least, and sometimes for a while later.
How do these vacuum releases work? Is there a release lever inside the cab that pops the trunk? Wouldnt the car need to be running to build a vacuum?
Vacuum storage canister on the firewall which is tied into manifold vacuum, vacuum release button in the glove box, vacuum actuator attached to the trunk, swivel actuating rod passing through the trunk lock
You are correct, as soon as the vacuum leaks down you use the key
Figure 1 is trunk lock only diagram. All the components in the truck were installed at Fisher Body so they aren't shown
Most everyone that pulled these from parts cars removed the actuator and the glove compartment button, but didn't get the rotating lock rod; it wont work without it.
This one is from a '66 Cutlass. Next to it is a valve cover bracket.
Some GM systems (early Chevy and Buick) use one of these instead of the vacuum reservior and switch.
When you pull on the ****, a plunger in the large plastic tube creates enough vacuum to operate the vacuum servo on the trunk lid. No engine vacuum required.
