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New member here :-). I recently purchased a highly optioned numbers matching big block '69 Corvette coupe. I wanted to make the interior like new again so a completely gutted the car's interior. During reassembly, I ran into a snag when I installed the center gauge cluster. I notice the center ac distribution outlet duct misaligned (off center). It was about a half an inch too far over towards the driver's side. This makes it impossible to install the wiper switch assembly with the ac registers. I should point out when I initially disassembled the dash, I noticed the center ac distribution outlet duct wasn't attached and was just forced in place so the problem was there when I got the car.
The ac distribution outlet duct attaches directly to the heater box and is held in place with a small screw. Either the heater box's or the duct's geometry is wrong as both are tied to fixed points. I only see one way these things connect so I don't think I'm installing the duct wrong. I've attached a picture of the heater box and the heater box with the as distribution outlet duct fitted on it showing how out of line it is relative to the edge of the driver's side lower dash pad.
Does anyone have any idea what's going on here? This is the 4th '69 I've done this type of work with but this is the first time I've had this kind of problem. I'm at my wit's end on this one. Could it be a wrong year part (duct or heater box)? I thought the components are the same from 1969 to 1976. I'd sure appreciate any help or advice anyone could offer.
Thanx, Everyone, and have a super Safe day.
Wild69
Thanx to those who responded. I ended up doing what I had originally thought to do, similar to a couple of suggestions from the forum. I cut the neck of the vent and moved the piece over about a half an inch to the passenger's side and fiber glassed in placed (I thought duct tape would be too Bubba-ish ). I took pictures of the sequence and attached below. Again, thanx to everyone who responded.
Wild 69
Last edited by Wild69; Jul 11, 2021 at 08:46 PM.
Reason: Update
I would cut that duct in the center. slide it a half inch inside itself and epoxy the H out of it with some good plastic glue. then it should line up. moving the heater box sounds near impossible. Could be the car left the factory this way.
Yes, I thought about that but I didn't want to resort to that sort of thing. Nothing has been forced fit thus far. It's hard to believe it'd left the factory like that but unless there's something goofy going on with the parts e.g. wrong year part or a poor reproduction piece, I can't think it'd be anything else. There's only one way the parts fit together and none of the screw holes are slotted. They're all fixed points.
Agreed but we want things as right as possible. I'm thinking I might cut the duct right at the neck where it enters the two round registers under the windshield wiper button and duct tape the offset. There's no practical alternative.
What makes this particularly infuriating is that I had the center gauge cluster installed and it fitted and functionally tested perfectly when I saw the duct was misaligned.
On my 73 the ac duct (top of gauge cluster) was not close enough to the fire wall. This caused the ac vent to keep from fitting correctly. On one of the many times it was removed, I disconnected the actual movable vents(two of them), and everything line up perfectly. My conclusion is that my Defroster duct is not against the fire wall like it should be. Since there was no way I was going to pull the duct and the heater box, I used my trusty Dremel to cut the plastic duct so it will accept the two top vents. Try to install your top bezel without the two moral vents and see if you get a better fit.
Sorry I can’t help you with fitment advice for your AC duct. The duct on my 76’ fit poorly and I have read many responses of others that have said the same. Quality control during our C3 generation was not good.
There is another problem you may encounter with the AC duct. Since our C3s’ are 40-53 years of age, the ABS molded plastic AC ducts are now aged to a point where they have become brittle.
I was reminded of this a few weeks ago when I removed my center duct piece from the storage box. Picking it out of the box with light hand pressure, it shattered into five or six pieces; mostly falling onto the floor.
My point is this. While the old duct may look good and solid, it is quite fragile. And unfortunately, the replacement piece you may purchase from eBay, or wherever, will be aged and fragile as well.
I agree with some of the other comments. Put it together the best you can and seal the leaks with refrigeration putty, refrigeration seal tape or whatever. If you push or pull on the old plastic pieces too hard they will fail.
Photos added of the broken piece and the replacement piece for reference.
As you can see, the neck for the center console distribution vent is gone
Replacement part, not shown, minor cracks in the upper neck vent
Please Help!!!! Heater Box/AC Duct Question
). I took pictures of the sequence and attached below. Again, thanx to everyone who responded.
