Topic: 71 Heater Core Replacement, not coming out...
in Forum: C3 Cooling and Heating Systems
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Rebuilding the HC: Using some off the kit's rolled butyl rubber on a sheet, make a frame where the heater core will sit. When re-installing new HC, it will stick and hardly move, so be gentle. HC tubes and fins are fragile. Dry-run the straps over the HC ends and see if the holes line up. If not gently move them into place. Then re-install the hold down straps.


On the other side, reinstall the metal plate with the 2 screws. Between the brass tubes, install the hold down clamp. Begin tightening it down, while gently "persuading" the tubes into the . Remember, this clamp is important. You'll be tugging and putting on coolant hose and clamps, so you want some strength here.
Clean all surfaces with a adhesive remover. This takes longer than the disassembly! I used a generic type like goo-gone but cheaper- worked great. But you also have to re-wipe with alcohol or windex before the contact cement for the gaskets (leaves a residue).
I used the kit's large perimeter gasket, but take notice: it has a few different ways it can be installed (see my finger), with slightly different corners.Get the fastest contact cement available- ine took too long to set up- and I wanted to be done.
Not knowing any better, there's a foam piece in the middle. I cut it out, as it isn't needed. Checking back in the cabin, it looks like it would work (or not). there was Butyl rubber down the middle seam between the AC and heater core on the firewall. I'll check again, when re-installing it.
One it lifted back down into place, you'll notice - because of the thick new gasket- the holes are hard to find AND- most important- the side Y bracket (with that TOP bolt that secures the metal inside) is not visible.
All you do is slowly use the top 4 screws and, once seated, it will start to pull down and it will show through the opening. Re-install Y bracket and 3 fasteners.



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Another thing about universal kits:

They don't fit all the time. Let's see: there's a side gasket, that supposedly will go on. It won't fit. So I had it glued in place- then took it out. I ended up using some small pieces of the felt-like material included in the kit. This gasket is way too thick- you can't begin to slide the RT side assembly over the gasket and around the HC assembly. Maybe other years are different. My 71 won't use it.
Either way, the RT side assembly has 2 front screws and one top screw holding it. Unscrew them, clean the ducts, then re-install using I eneded up using soem felt and slits of duct tape- hey it worked. It won't rattle and I had a small crack on the seam- another reason why the gasket made the probelm worse- it would have snapped if i'd have forced it over the gasket.
So, using duct tape solved my crack and sealed it up nice.
Another thing about kits: Where are the rubber seals and flapper door to repair/refurbish/rebuild inside materials? All-incompassing kits= yeah, right.
Nowhere does this kit include redoing the whole assembly. There are a lot of cars out there with worse HC assememblies than mine- say sitting out in the elements/junklyards, etc.
Sooner or later, a TRUE rebuild kit would make sure to have everything needed.
That said, mine ionsides are fine, seal wise. the flappers were still soft and bumpers (so it doesn't just open and make a noise) were still present and OK. If the inside rubber guts are bad- you're outta luck and will have to make your own.


And again, here's some "extras"- not like my seal i pulled off (anmd left on the vacuum hose in the car). Afterwards, the vague diagram listed them as AC evap seal parts for the firewall. Ok. Where's the new piece for mine?
And, last but not least....
The heater tube seal. A pain to stretch-pull on (gentle, though)- which way does it face? Yes, one tube is bigger, and the gasket has a small hole and a larger hole. But the darn gasket can be flipped, you know.
You have to check back in the cabin of the car. In the car (shown in the pics) the gasket's curved end coincided with the left side. Now install that on the tubes correctly.
So, there's more to come.
This whole experience has me almost contemplating doing a detailed article on my blog
after, of course, this is done.
I know it was rushed, and the pics weren't perfect, but I feel it's my duty to pass on this info, especially for hard this was to find detailed info about AC cars.
Moderators... thank you for not kicking off the post from mistakenly posting in the wrong area and not in the heating/cooling section.
A few more things: I'm not afraid to admit when I'm wrong.
I screwed up the large gasket. Looking at the diagrams and Zip sheet, I thought it went in between the heater core metal box and the plastic heater housing. This gasket actually is the seal for the firewall, that's why there is a middle seam part (which I mistakenly cut out- it's the divider between the heater brass tubes/coollant hoses that go to the right side; the left is the AC box.)
Well, there's only seals in kit forms, so I couldn't just by a new seal. But there's a better alternative:
I stumbled on the AC isle at a local mart. All those foam/rubber seals for windows, well, there's the soliution. There's an exact match in a rolled up sealer, even with adhesive strip on the back. It's the exact size and width, too!
So I did a perimeter frame and this seal will probably be even better than the actual kit.
Cost: $3.00 (with lots of leftovers for other "auto" needs.
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Oak Creek, WI - USA
Joined: 5/21/2008
Posts: 1965
Vette(s): 1981 Great White Shark. Red Interior, 350/190 hp. PS, PB (SS), A/C CC, T-Tops. Served three years in Active Duty Army, then Retired Air Force after 34 years! Badger State Vettes Car Club. 175,000 Original miles!! Now own a 1998 C-5!
Great Pictures !
Dan

So the last couple pics show "restoring" the windshield /heater vent area. This one is easy; you really can't screw up. After you unscrew 3 bolts on the back, the two "swivel" vents come out.
Here you tear out the old seals and clean real good. New seals are shown as being too long for my '71. All you do is cut them to length. It's hard to get your fingers in there, but take your time and stick 'em in place. Bolt everything back together and the vents are definately "snugged" in there and stay put when you aim 'em.
Notice I didn't repray the outside. It looked decent enough. I did, however, really clean it well, including taking off the electrical switch before, obviously squirting with any cleaners.
Forgot to mention the vents themselves. The chrome/silver painting on them was worn off in areas leaving them an unmatched pair when viewing from the front.
My solution: I thought it would look fine black (under the chrome) so I got out the fine steel wool and "buffed" the chrome away, leaving it all a clean black. I think it stands out more.
Great job, Aaron, but you made me feel even better about replacing my heater core while they were rebuilding my A/C system!

Barry

in Forum: C3 Cooling and Heating Systems
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