Anybody completely take apart their heater boxes to restore the blend doors and such? Question I have is, I've gone thru the heater core box and now am looking at the blower box which appears to be hermetically sealed. Of course with the proper determination I can get anything apart, but getting it back together so it is functional is another story. Blend door foam was non-existent on this adventure and am wanting to get everything sealed up and quiet. Vehicle in question is an 86 pickup with AC

 

I dont have pics , but I have done it a few times .
3m panel bonder is your friend , I use #08115

 

So splitting the case------did you drill out the dozen or so small melted areas to separate? For getting back together I was considering the Gorilla Glue adhesive, but the 8115 looks more user friendly

 

Well I pulled the plug on this and went for it. Sanded down the little nubs that were factory melted in down flat to the case. Took a 1/4'' drill bit and went into the holes till it stopped. ( It was like hitting a harder plastic) Took my sharp knife and scribed a line across this area and followed up with a 32t hacksaw blade to further score the edge of the case. (still tight) drilled down further until the bit went all the way through. finally got some movement, back and forth with wiggling , cutting with the blade and scoring areas with my knife where the blade wouldn't cut. Then all of a sudden the whole thing just pulled apart into 2 nice pieces (patience is the key here). Further disassembly and cleaning with soap and water along with attaching new foam to the door. I didn't use the 08115 epoxy. Reassembly commenced----- I already had a tube of clear silicone adhesive that I dabbed where I had drilled (had to fill the holes anyways) Squeezed the case halves back together tight and used a couple of pieces of packing tape to hole them together and 'Voila' --set it on my bench for the silicone to cure overnight. Sorry--- didn't take any pics of the process, just got into it and didn't stop

 

I also replaced every piece of foam when I had everything apart to change the heater core. One thing I suggest is to use extra adhesive on the inside/outside blend door replacement foam. The foam I used had an adhesive backing but that did not hold well after some time.

 

Of course I don't know what brand foam you used, but the material I got was from Blend Door USA . You have to be very careful after you peel the back off this stuff. Just about when you apply this stuff, you'd better have it where you want its 'cuz it's not coming off