Need some help- firewall heater nut removal

64Rivvy · November 18, 2015

Hi,

I'm replacing my heater core in my 64 and following the steps in the service bulletin from the roa tech tips section for an a/c car. I have the console, pass dash pieces, heater controls and everything disconnected. I've removed 7 of the 8 firewall side heater box nuts but I can't get the last one out.

It's the one farthest towards the pass side fender on the bottom closest to the blower motor. It's at a strange angle and I can't seem to get a socket to hold onto it and I can't actually see it. Any tips or tricks on this? Maybe I need a thin wall socket? It doesn't seem like I can drop the evaporator and start pulling out the rest of the heater box until I get that last one out.

Thanks.

RivNut · November 18, 2015

I pulled my evaporator and housing without removing the heater core and I removed a heater core for a friend of mine a number of years ago without messing with the evaporator. It's been too long to remember anything but scraped knuckles, but it did come out.

Ed

64Rivvy · November 18, 2015

Don't those bolts hold the whole assembly to the cowl/firewall though? It seems like it's being held on right at the spot where that

Last nut won't come off so I don't want to pull on it too hard and break it.

fatbuick · November 19, 2015

I wrote an article with pictures of the whole procedure. http://www.mako.com.au/buick/assets/images/63-65heatercore.pdf

Point 1 reads) Remove 7 speed nuts around the air inlet assembly on the engine side. There is a 8th
speed nut below the assembly cover which can be removed after the cover is off and out of
the way.

Could this be the one you're having trouble with?

64Rivvy · November 19, 2015

Tony,

Thanks I was just coming to post that I found a great article last night from a gentleman in Australia explaining that the heater box needs to come off to access that last bolt. Looks like it was your article! To take the heater box off the firewall do I just need to remove the few bolts around the flange and unhook the two cables that are attached to the box? It all seems pretty brittle from age so I'm trying to be very careful to make sure I remove all the bolts/fasteners before I start yanking on it.

Thanks,

Raul

fatbuick · November 19, 2015

Hi Raul,

Gentleman! I like that.

Remove all the bolts you can and the cables and remember mine is 65 so could be different.You really just need to give it a go and try everything gently.Best of luck

64Rivvy · November 22, 2015

I had to go through the outer rings of hell to get it out, but finally got the heater core out. I also removed the evaporator. I'm going to go ahead and replace and clean/re-spray everything for the heating and cooling system while I have it all out. I also found the pass floor was hiding some rot under the rug so I'm replacing the pan. This is the domino effect in action. I started with just replacing the heater core but decided hey, I might as well replace the insulation, all A/C and heating system parts, paint the floors and put in dynamat throughout, do the carpeting, re-upholster the seats/replace the seat foam, and restore the console and passenger side of the dash while it's all out. It will be great to get it all done but now my weekend project has gotten a whole lot bigger..

Here are some pics of everything removed. Definitely going to need a new inner heater core box and mounting straps or will have to do some fabrication to repair it. Luckily it seems like all my vent doors and springs are in good shape and working well.