1968 Heater core replacement

[p51]

My heater core is leaking so I need to replace it. I thought before I dove into the project that I would ask for any tips you guys might have.

Details: I also have factory AC so this is going to be a bit more difficult than w/o AC. So far I've removed the AC compressor (had to remove it to replace the timing chain recently), removed AC and heater hoses, and bypassed the heater coolant connection on the engine. I pressure tested (with air) both the heater core and AC heat exchanger - sure enough there was a leak in the heater core but fortunately none in the AC. I've got the following docs to work from (1) Shop manual, (2) Assembly manuals, (3) Haynes manual. Any suggestions, tips, books, or links to on-line how-to videos/posts would be much appreciated. I've already found a few and am now reading posts/watching videos. There are two videos on-line - one from West Coast Cougar and another from AutoRestoMod that deal with the heater... I'm fast becoming a bit of a "youtube mechanic" :grin:

Thanks
James

 

[dalorzo_f]

You pretty much have to remove the entire under dash setup the blower and box sections.

Bolted to the firewall in, IIRC, 3 places with stamped nuts on the firewall in the engine bay. One screw to the dash on the upper RH side. Need to pull the hoses and control cable, and I found removing the glove box also gives added access/visibility.

I think I recall removing the dash support brace too.

Ford designed it with about 1/32" clearance to get it in and out so its a real "fun" job.

Probably seen it but this is a decent video, if you skip the first 8 mins or so...

https://www.youtube.com/watch?v=3UkTsI_fnkw

As the fades/cuts show, not a straightforward install. It "can" be done by one, but two people make it less painful (as its never "easy")

 

[robert campbell]

Jack the car up a bit and remove at least the passenger front bucket seat. If you have a center console, remove it. Your back will thank you later. also wonderful to have an assistant ant the ready to hand tools. I hate getting in the car and laying down and then need to get right back up.

Also a battery spider light is way handy under the dash. It has magnetic feet and can really shine the light in the right place.

http://www.amazon.com/Stanley-SB010...=1452714817&sr=8-2&keywords=spider+flashlight

Rob

 

[p51]

Thanks guys. Exactly what I was looking for - the inside tricks/tips to make this go easier...

 

[p51]

OK. I finally got around to taking out the heater/ac box. Thanks for all the tips... they were very helpful... but boy it was still a pain in the a** getting that thing out.

So, I go it out but in doing so I broke off the ~1" fiberglass drain spout (for AC condensation, I'm assuming) on the bottom. Any ideas on how to fix something like that?

 

[dalorzo_f]

Going to be hard pressed to epoxy the spout back on and have it hold. Depending on how the break is you could try fiberglassing it.

I don't recall the size but you may be able to sleeve a short piece of copper tube (less corrosion) inside and glass around the break. Without some internal structure you may have to build up a too thick patch to get the drain hose back on.

Another option may be to drill out the drain area, flare a short piece of copper tube (don't recall the spout size, but think its about 1/2"). Glass outside, paint, a bit of resin on the inside to smooth out the interior to prevent pooling of any condensate.

 

[Ruppstang]

I have fix several of them with JB Weld epoxy with no problems. You think getting it out was hard wait till it goes back in. Holding up there and lining up the studs in the firewall can be challenging. I would get some help for that.
Marty

 

[p51]

Thanks for the quick responses...

I too was thinking about slightly increasing the size of the hole and inserting through it a copper tube with a "flair" on the part that will be inside the box. Then gluing it in with epoxy/fiberglass. Good to know that JB weld works as well. I'm pretty sure that it broke off when I was maneuvering it out (slight twist, pull, repeat). Now I'm a bit worried about damage when putting the box back in.

Just FYI: One suggestion/trick from AutoRestoMod about lining up the studs that go through the firewall is to put some rubber tubing over the studs, pass it through the holes in the firewall and use it (with a helper) to get good alignment... (see ~9m30s point in video)

https://www.youtube.com/watch?v=3UkTsI_fnkw

 

[robert campbell]

I have been using this stuff vice J/B Weld lately. It is far less "gooey" and works great on a surface that is vertical. But in your case you can more than likely get this repair horizontally. But a nice tool in the tool box!

Rob

http://www.acehardware.com/product/index.jsp?productId=3506526

 

[p51]

OK. Need some more advise/tips/thoughts...

I've got the heater/evap box disassembled. Since the heater core was leaking it needs a:
(1) Cleaning. I was thinking using Dawn and scrubbing it down. Followed by:
(2) Removing rust from all the metal pieces and then paint with some rust inhibitor paint before adding new seals

The heater/evap box is in good shape (except for the drain nipple). But gosh it sure does seem fragile. I was thinking of maybe sanding it down (lightly). Then covering it (inside and out) with a light coat of epoxy for reinforcement, and then preping/painting the outside. Any thoughts/concerns on whether this would be a good way to reinforce the box? Other ways.

I have pressure tested the evaporator (using a MityVac) and no leaks at ~15psi. The heater core under the same test leaked did leak. Anyone know what pressure the evap core is supposed to hold? I want to test it to its spec'ed pressure.

Of course I will get a (1) A new heater core - brass not aluminum (2) heater core end covers (3) an AC seal kit (4) some new AC ducting tubes. Anything else that comes to mind?

Thanks

 

[franklinair]

On the evaporator: I'd do a Vacuum test (same as you do on an A/C system when checking for leaks). But since the low pressure check was OK, I wouldn't expect a vacuum leak.
I'd also flush the evaporator to remove any residue potential. In fact, I'd flush the entire A/C system prior to replacing the drier. (Flushing fluid available at Advance Auto) I just squirted the fluid into the system, let it set for a while, then blew out the A/C system using low air pressure, and then hook up your vacuum pump and evacuate the system for 8 Hrs+/-. Then check your vacuum gage 24 Hrs later to make sure the vacuum has held. Then charge with Freon if OK.

As far as the box assembly after you fix the drain, I'd just clean/sanitize everything and just spray (aerosol) satin black.

Also- check all the vacuum valve units for operation and NO vacuum leakage.

Neil

 

[p51]

On the evaporator: I'd do a Vacuum test (same as you do on an A/C system when checking for leaks). But since the low pressure check was OK, I wouldn't expect a vacuum leak.
I'd also flush the evaporator to remove any residue potential. In fact, I'd flush the entire A/C system prior to replacing the drier. (Flushing fluid available at Advance Auto) I just squirted the fluid into the system, let it set for a while, then blew out the A/C system using low air pressure, and then hook up your vacuum pump and evacuate the system for 8 Hrs+/-. Then check your vacuum gage 24 Hrs later to make sure the vacuum has held. Then charge with Freon if OK.

As far as the box assembly after you fix the drain, I'd just clean/sanitize everything and just spray (aerosol) satin black.

Also- check all the vacuum valve units for operation and NO vacuum leakage.

Neil

Thanks Neil. I'm actually not planning on re-hooking up the AC right now although I am planning on testing/re-installing the evaporator core in the box (because I don't *ever* want to reinstall a heater box again). I don't plan on hooking up the evaporator core or reinstalling the compressor (which I had remove to replace a slack timing chain) etc... I'm one of those people who thinks "running the AC" is opening those tiny windows and driving 50mph :grin:

Thanks for suggestion on the vacuum motors/valves. Looks like another job for MityVac :wink:

 

[franklinair]

We southerners gotta have A/C.:grin:

Neil

 

[CougarCJ]

As far as the box assembly after you fix the drain, I'd just clean/sanitize everything and just spray (aerosol) satin black.


Neil

It should be a medium to dark gray color. :wink:

 

[franklinair]

Yeah, I know- but the satin black looks better IMHO. (Just part of my personal touch.)
Does that qualify my cars as a 'resto-mod'?:wink:

Neil

 

[Ruppstang]

I would not coat the inside with anything if you have no breaks. A lot of it has close tolerances and thing may not work properly even if you only add a small amount of thickness. I have good luck cleaning with Dawn and a scotch brite pad then just wiping two coats of Maguire's 40 vinyl and rubber treatment. It restores it back to it's original color and finish.
Marty

 

[dalorzo_f]

Marty, only meant around the repaired drain hole, if necessary, to ensure there is no recess to hold fluid...

 

[Ruppstang]

This is the statement I was referring to.
"The heater/evap box is in good shape (except for the drain nipple). But gosh it sure does seem fragile. I was thinking of maybe sanding it down (lightly). Then covering it (inside and out) with a light coat of epoxy for reinforcement, and then preping/painting the outside. Any thoughts/concerns on whether this would be a good way to reinforce the box?"

 

[p51]

We southerners gotta have A/C.:grin:

Neil

Yep. I was born and raised in the South so I know what you mean.

BTW: I've never been to Franklin, NC but if it's anything like the area around Asheville (which I assume it is) it is one of the most beautiful areas in the US.

 

[p51]

I would not coat the inside with anything if you have no breaks. A lot of it has close tolerances and thing may not work properly even if you only add a small amount of thickness. I have good luck cleaning with Dawn and a scotch brite pad then just wiping two coats of Maguire's 40 vinyl and rubber treatment. It restores it back to it's original color and finish.
Marty

Thanks. Yeah, I was planning on avoiding doing anything near the seams, flapper doors/frame, etc. I am planning on painting it black... I've got a black interior, carpet, dash, etc and I'm thinking it will look better than the original grayish color.