Heater Y-duct install

[Ronald F.]

When I acquired my '67 L71, it was missing the Y-duct. I've since acquired an original piece and would like to know if there are any specific sources that explain exactly how to install it and what bolts/screws to use etc. I checked the Service Manual but saw nothing about removal/reinstallation of this piece. Any help would be appreciated.

Thanks!

Ron

[Tom R.]

Re: Heater Y-duct install

The Y-Duct uses two hex head screws and their location and installation are clearly shown in the Assembly Instruction Manual.
Tom

[Ronald F.]

Re: Heater Y-duct install

Thanks, Tom. Where can I get this AIM?

[Joe R.]

Re: Heater Y-duct install

Ron,

You can get 'em here:

https://www.ncrs.org/shop/index.php?main_page=product_info&cPath=1_67&products_id=224

Joe

[Richard M.]

Re: Heater Y-duct install

The AIM is a must for any Corvette, but unfortunately it doesn't help here. The (non C60 (A/C)) heater & defroster box came to St Louis as an assembly, Part# 3838355, shown on UPC 1 Sheet D6. Until you get your AIM, below are some pages from it for reference. See the pdf.

For A/C boxes, which use a different Y-duct than non A/C boxes, it shows "Distributor ASM" 3846156 on UPC C60 Sheet A2. One screw is part of the radio side trim panel attachment, and the other screw the duct to the box as part# 9419303. It appears to look like the hex head with captive flat washer as I believe is used for the non A/C box to Y-duct screws.

Note that the upper defroster duct is not designed to attach to the box, It attaches to the upper dash and sits above the box oval outlet, about a inch or so. These typically get damaged as the lower flange is very thin.

Below are some shots of a '67 heater box I restored a while back. They may help.

Rich

htrbox.pdf

[Ronald F.]

Re: Heater Y-duct install

Thanks, Rich. the one in pic 2 is the one I bought. Is that the one for a no A/C vette?

[Richard M.]

Re: Heater Y-duct install

Thanks, Rich. the one in pic 2 is the one I bought. Is that the one for a no A/C vette?

Yes , I probably should've mentioned it was non-A/C. ooops.

There are 2 holes for the screws as Tom said. You can use anything that'll fit, but the originals had that little hex head, 1/4" drive IIRC. You can probably see others on the box which mount the brackets & cable clamps, etc. You could always "borrow" those which can't be seen and swap 'em out to hold the y-duct.
The problem sometimes is the holes in the heater box to accept the screws get sawed out from over tightening as the fiberglass isn't made for torque.

Rich
p.s. quick pics of the C60 A/C sheet showing the y-box and the screw of suspicion(item #5).

[Ronald F.]

Re: Heater Y-duct install

VERY helpful! Thanks a bunch, Rich!

Ron

[Ronald F.]

Re: Heater Y-duct install

Rich, Zip corvette has the screws, 2 in the set, but the diagram on the website shows the y-duct for the A/C car. Are the screws the same for non A/C? BTW, I thought there were 3 screws needed, 2 on driver's side and 1 on passenger side. Am I missing something? Also what size and color are the screws?

Thanks,

Ron

[Richard M.]

Re: Heater Y-duct install

Ron, Sorry but I don't have that info. No midyear car here to check & I was going from memory. It may be 2, or 3 screws, I forget.

Someone else will jump in with the answer and maybe some photos.

Rich

[Tom R.]

Re: Heater Y-duct install

Unfortunately my car has C60 and there are two small hex head screws on the Y-duct main throat to the heater box then one trim chrome Phillips screw with a captive washer that connects the radio trim panel to the Y-duct left extension. That would be three.

[Richard M.]

Re: Heater Y-duct install

Ron, many vendors package parts so you have to buy extra. Example is the seat frame bolt sets for the 58-60's. They're also sold to be used for fan shroud/radiator mount bolts. Those require 8 pcs. The package has 8. The seat frames use the same bolt, and require 7 per side. If you need seat frame bolts, you get 2 extra per car.

If you buy 2 pairs of the screws you'll have enough. I somewhat recall they're the cad plated hex head type but with a captive loose fit flat washer. I'm not positive. If you discover these should be zinc/cad plated, a little silver paint and you're done. If you want originals, I'd suggest Richard Fortier, who's in the Driveline.

Rich

SF-518