I have a 69 roadster, and the the two vents in the rear deck stays open all the time. I can manually push in the actautor to operate the vent, however I'm not sure what actually activates this...mine stays open all the time. Is there a switch somewhere to control this?

|UPDATED|5/17/2004 9:46:47 PM (AZT)|/UPDATED|

Rear deck vents are controlled by a vacuum actuator located on the passenger side. The vent control rod is connected to the front side of that actuator. The vacuum line comes in from the rear.

Hope this helps.

John

I'll have to check to see if the vacuum hose is connected then, because mine is not working. What actually tells is when to open or close? Is there a swtich somewhere to manually do this, or is this automatic using some sort of thermal sensor? Thanks for your help...

I think when you move your heater to defrost. Then the vent should move. It is only open in one of the settings. Also the line runs down the drivers side of the piller next to the seat. It then should turn to a metal line and run under the carpet behind the drivers seat.

|UPDATED|5/18/2004 6:40:48 AM (AZT)|/UPDATED|

Thanks! I'll check that out...not much is written on that rear Astro vent that I could find. I know my defroster is in the off postition, so I'll check for a vacuum leak.

mine just had a piece of rubber tubing joing two metal lines behind the passenger seat..

it was dry rotted..

if you dont have one already..

invest in a hand vacuum pump and start with the vent actuator and work backwards from it.

cthulhu said: . . . if you dont have one already..invest in a hand vacuum pump and start with the vent actuator and work backwards from it.

ABSOLUTELY

A $20 "Mighty-Vac" from TwilightZone can save a C3 owner a fortune AND a lot of time. Without one, you'll have to SWAG alot of problems. Kinda like playin' darts with a blindfold on!

Good Luck

John

Thanks guys, I'll pick one up this weekend. I was researching the net on anything that I could find as to how they get activated (opened/closed) but wasn’t able to dig up any info. What I did find out was that they were supposed to pull the heat out of the vehicle using the principles of Bernoulli…that’s when the air rushing over the rear deck is faster than that which travels under the car thus creating a low pressure in the area directly outside, and above the Astro vent which in turn moves the hot air out of the vehicle. Well as it turns out the gas crunch of the seventies forced the auto makers to reduce drag on future production models, they did this by way of wind tunnel testing; after which they soon found out that the low pressure they were hoping for wasn’t there, and discontinued the rear deck Astro vent due to its ineffectiveness.
However I have one, and I want it to work. One person said that they believe it to be activated when the defroster is turned on; which stands to reason since the air induced into the vehicle needs an evacuation point. I can’t test that yet, till I figure out why mine are staying open.

Tech tip: I was replacing the interior screws in the door panels last weekend, only to find out that the previous owner used a larger slotted head screw. He did so probably because the original screws had been over tightened. This worked, but further mushroomed the hole outward and I wanted to use the original looking screws with the button washer. Now my tech tip…I placed a ball peen hammer on the hole, and with another hammer gave it a couple of smacks, thus closing the diameter of the hole till the replacement screw fit.

Feel free to move these to a more appropriate place, but I have one other also.
The black tar holding the plastic protective layer in place to the door directly behind the door panel had lost its tack, and was all dried up and brittle, so in a pinch I used a bead of plumbers putty to re-adhere. It supposedly doesn’t dry out, discolor, stain, and had excellent adhesion till I was able to refit the door panel to permanently hold it in place.