Heater Box and ducts
Can anyone recommend something that details the heater box subassembly and its connections to the defroster and floor diverter? In taking things apart to get to the radio, clock... I found that the end of the heater box - where it connects to the floor diverter is broken (missing). The box itself is a good 2" below where is should connect to the defroster duct. Was it installed improperly when the last heater core was replaced? The floor diverter duct was layting loose behind the radio. I can take the heater box off and try to repair it but I don't have a good detail what its suppose to look like or how the ducts connect. None of my books have a clear image of what the end of the box looks. I suspect I could use fiberglass to rebuild the end of the box. The box looks good where it attached to the inside of the firewall (passenger side).
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Re: Heater Box and ducts
John, this is a 64 box, it's essentially the same as a 67. The 63 box is rather different, so my pictures will not help you.
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Re: Heater Box and ducts
John, Here are a few shots of a 67 box I rebuilt. The diverter attaches with several scews to the end of the box. The photo with the blower shows the end of the box in the background. I looked for more detailed pics but came up empty.
Rich
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Re: Heater Box and ducts
Found a few more. The diagram came with the seal kit I used when I rebuilt it. I also seem to recall that the defroster Y duct was sitting quite far above the diverter, maybe an inch or more. It doesn't need to be perfectly sealed. The air will still flow to the top.
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Re: Heater Box and ducts
Hi Harry, Thanks for the link.Comment
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Re: Heater Box and ducts
Richard -
There is a gap (by design) between the defroster outlet on the heater box and the defroster yoke, to isolate the defroster yoke from noise/vibration from the heater case; if they were connected, the main fiberglass upper dash panel would act like a drumhead, amplifying heater case noise/vibration. Having an air gap between the heater case defroster outlet and the defroster yoke inlet was standard Chevrolet design practice.Comment
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Re: Heater Box and ducts
Thanks Richard - those are going to help. Odd that the box and defroster duct don't connect well.Comment
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Re: Heater Box and ducts
Thanks John. That's interesting (and encouraging that I'm not missing some kind of connector). The end (of the heater box) that connects to the floor diverter is another issue. Mine is missing some rather large chunks I'm afraid. I'd like to get my hands on a correct unit so I could see what its suppose to look like.Comment
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Re: Heater Box and ducts
Here is the photo from Richard Mozzetta of a good box along with 2 photos of my box. It looks like there is some fiberglass missing (see circled area) on my heater box. Richard also appears to have a hole (perhaps for attaching the floor diverter). My diverter just falls off of the heater box. Also there is a hole on the box (see arrow) that looks like it could attach the heater box to the firewall. zbox1.jpgxboxwmarks.jpgIMG_0412.jpgLast edited by John G.; November 1, 2012, 08:49 PM.Comment
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Re: Heater Box and ducts
John,
That piece you're missing is the reason the diverter won't attach. If you look at my 1st photo in post #3, you'll see a small hex head screw holding it on. It's gone on yours.
You'll have to repair that section of your box so you can attach the diverter with a screw. I recall there is either a metal nut plate for a machine screw or plate for a sheet metal screw to hold it on. You can also see the nut plate/screw plate in my photo you referenced.
That big hole in your photo with the arrow......... That is to attach that end of the heater box to the firewall. There should be a stud mounted on the firewall that the box fits over. When the box is installed, that hole lines up over the stud and a big pal-nut holds it on. Look behind the insulation.....the remnants of the broken piece may be there.
The assembly pal-nut is shown in the AIM, UPC 1 ASM, Sheet D6, item 4.
The firewall stud is shown(I think?) in UPC 1 Bolt/Weld Sheet A12, Item 12 "Bracket". It's a riveted plate with the stud attached and the stud protrudes from the engine bay side of the firewall into the cabin.
RichComment
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Re: Heater Box and ducts
As Rich indicated you will have to rebuild that section. It is rather easy. You will need to locate some fiberglass the same thickness as the heater box. Obtain some resin and fiberglass cloth. Cut the piece of fiberglass you obtained to fill the area where the piece is broken off. Only trim the areas where the the replacement piece will attach to get it relatively smooth. Do not worry about the area where the screw goes in yet. Mix some resin with the hardener and attach the replacement piece using the fiberglass cloth on the inside of the box. After it sets up you can add another coat of resin, after that sets up you can sand the area to make it smooth. The area where the screw goes in is just a thicker area of the fiberglass. Trim the fiberglass to look like the picture of the complete box. Slide the diverter over the area and mark where the screw will go. On the inside of the box attach, using resin, a small piece of the fiberglass you obtained. When it sets up, drill a starter hole for the screw. Use a self tapping screw to cut threads in the double layer of fiberglass. You should be all set to go. Also, move all the flappers to ensure you haven't created any restrictions on movement with your repair.
Good Luck
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Re: Heater Box and ducts
Okay. Maybe I can get to it without taking the heater box out. It would be nice to have one less rattle.Comment
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Re: Heater Box and ducts
DCP_0949.jpgDCP_0952.jpgDCP_1006.jpgI had to do some rather extensive work on my box. A few pictures to help you visualize.
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Re: Heater Box and ducts
I sucked it up and decided to remove the heater box while it was warm. It appears as though I have problems similar to those of other mid-year heater boxes. Only two studs were solidly attached - one was there but broken off - the other was missing entirely. The upper stud that remains in place has a crack along one of the rivets. So there is going to be more work than I thought. I'm still considering how I want to repair the studs - obviously not a very robust design.zboxdamage.jpgzstud.jpgComment
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