My Heater Box Restoration

Hey guys,

I have just finished rebuilding my heater box. Before I began, I couldn't find a whole lot of 'how to' info on the net so I thought I would share my experiences.
The first thing to know is that it definitely is not 'rocket science', but you must be careful and methodical and documentation is a must. Make sure you take plenty of digital photos.
I bought my rebuild kit from DMT and it is a good one. It has all of the parts that you need and some instructions with it.
Step 1: Disconnect tubing


Step 2: Disassemble all of the plastic parts


Step 3: Remove spring clips and gently pries open the two halves. They will be quite stuck as there is a gasket between the mating surfaces. They have been together for 40 plus years so it's no surprise. Its important to note that the box is quite brittle and will break if forced, so be careful.



Step 4: Remove heater core and ac evaporator (if equipped).

The inside of your box will undoubtedly look similar to this.


Step 5: Strip all remaining items like actuators and brackets from the housing. Then thoroughly clean it. I used a couple of methods. First I pressure washed it (not heavy) and then to remove the stubborn gasket material, a blade and a light wire wheel.




Step 6: Remove all the sticky residue. Use denatured alcohol to make sure you get good adhesion for your foam.


Step 7: Treat and paint all rusty brackets, actuators, screws etc.


Step 8: Visually inspect and pressure test ac evaporator and heater core. Flush R12 freon out of evaporator so it can be replaced with R134a. You must never mix different refrigerants.


Step 9: Continue to install the rest of the foam and reassemble the box.



Step 10: Re-install the heater core and evaporator. In my case, the box was quite weak and broken around the screw holes for the evaporator. The evaporator has a bit of weight in it and the jarring from driving would have caused this to happen.

I made a steel plate to install as a washer to mitigate the problem.


Step 11: Clean and reconnect up the tubing. Inspect it for cuts and splits.

Step 12: Test with a vacuum pump for functionality. The last thing you want, is to install it into your car and it doesn't work properly.



I hope this helps people that are wanting to tackle this task. Good luck.

Thanks for an awesome right-up Jason. :headbang: Makes me wish I had A/C in the car now....

Nice work Jase, thanks!

Got a Mityvac, just need to chase up a kit .

Yep. Stuff sure does add up over the years!

Oh, that brings back memories of doing mine!!!! Nice job on that one!!! I found an old bowling scoring pencil in my heater box along with some leaves!!! hahahahaha

Hey Jase,

Got my kit from DMT....much involved in removing the box?

My car is an aircond car too.

Hey Mr Gorsky,
Its not too much drama. There are a series of bolts through the fire wall that you need to undo. Also a little vent pipe that is usually save able. Unhook the wiring to the fan motor and unplug the tubing from under the steering column. Also, there is a bracket at the top of the box under the dash. It's super easy if you remove the dash, but I believe you can get it out by taking out the glove box insert. Good luck with it and if you have any questions please feel free to ask. Be prepared, it's a lot of work but really worth it.

My front seat is still out so I've got plenty of room to wriggle around under there. Thanks for the help.

Cheers

looks good =0)

Removing the blower motor (3 small sheet metal screws that surround it in engine compartment) helps a LOT when getting the box in/out. The service manual will walk you through the steps fairly well.
I found that this is a great time to carefully disassemble, clean, and add some new dielectric grease to the fan speed switch. The Fury's was showing some evidence of heating due to dirty contacts.
I patched minor holes in the ducting (hoses) with an old linen cloth and some very flexible RTV rubber. Tomorrow, we'll weld a broken defroster diffuser with plastic welding equipment from the Horror Fright store.

Thanks for the helpful thread!!!

That was an awesome detailed explanation Chargerjase. There should be a site specifically for these step by step proceedures as a guide for the rest of us. My 69 Coronet is an AC car also and I will refer to this as I get there. Mocajava

Nice job Jason. I pulled the heater box out of the Belvedere years ago thinking I would eventually get around to rebuilding it. Haven't got around to it yet. For now I'm using solar heating (park in the sun). I'll keep this thread and maybe it will inspire me to get it done, we'll see. Thanks.

No worries Moparsmitty. If you would like a more detailed version, you can find it here as well as loads of other great info

http://www.retrorarities.com/images/HeaterBoxRestoration.pdf

Anyone have any pictures of where all the clips go that hold the halves together?

I have 9 clips, and have the 'j' nuts on the two ends (4 total) but wondering if there should be a few more screws to retain the halves or if it's all held with just clips.

Thanks.

EDIT:

I kind of answered my own question. I found this post http://www.forbbodiesonly.com/mopar...uestions&p=910197868&viewfull=1#post910197868 and it shows a few more screws being used....so now the search begins for the missing clips and screws.

I just took apart a unit out of an old 71 I had and was supersized to find the two halves held together entirely with the J-nuts and screws, none of those spring clips like on my other 72 unit.

I also found these little tips on the back-side of some of the screws....never saw them before.



Bonus, I was able to take the actuators as a few of my other ones were bad.

Hey Suregrip. Sorry, I missed your post from December. I'm sure you know by now, but yes 4 screws and the rest are clips. If you need any additional pictures, let me know as it's not installed in my car yet.

What type of caulk should you use before the large gasket?? I don't have it or misplaced it when I moved. Thanks.

The caulk comes in the pack. If you have lost it, it is a rubber type compound. It is soft and pliable with a consistency like plasticine. Sorry I don't know the name of it. Maybe you can contact http://www.detroitmuscletechnologies.com
and ask them if you can buy some off them. Good luck.

Do you by chance still have the instruction sheet that came with the kit. I bought 3m spray adhesive. Idk what happend to the calk and instructions.