Heater box replace or repair

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Joined
Nov 28, 2014
Messages
119
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14
Location
Charlotte
My Car
1973 Mustang Convertible.
Restoring and fixing as I go.
Looking to clean up the heater box, and when I did , I noticed the piece of plastic missing near the vent.

Can this be repaired or is it better off getting another heaterbox (non/AC) ?



 
If the rest of the box is in good shape I would patch it. You can make a patch out of some fiberglass cloth and resin. You can use a piece of cardboard covered in wax paper fitted in the end as a mold. The resin will not stick to it. Scuff up the area around the edges and put a piece of fiberglass cloth soaked in resin on the outside. Once this has set you can remove the cardboard and do another strip on the inside if you want to double up. Make sure you scuff up the first piece before overlaying it. Should work ok since this is a area where there is no stress. I have done several over the years on heaters boxes and vent tubes. Still holding strong.

 
For small holes and cracks in the fiberglass, I use JB Weld. It works great and the color matches the original nicely.

 
I think that is a common problem caused by big feet. Because nothing connects to it and it's not visible, unless you crawl under the dash, I would just smooth it off. If you're trying to make it concourse correct, or showroom fresh, I would try patching it first, by smoothing out the broken end and use a good adhesive, like epoxy or Plastic Bond, to attach a patch to replace the broken section. You should be able to find a piece of strong plastic, like ABS, that is the same thickness.

 
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If you go with a new heater core be sure and pressure test in water before you install. 10 - 15 lbs. of air pressure in a bucket of water. I have had two that were bad out of the box and both were Ford made not the aftermarket. It is a pisser to get it all back together and it leak. Did once never again.

You should be able to get a used one cheap. When you get into it the foam will be bad you can get a kit to replace all the foam. When you take the shafts out of the trap doors be careful to support the plastic as you drive them out or you will break out around the shaft. Once you get it apart I take a long 3/16" drill and run in the space where the shaft goes to loosen it up some for easier assembly. 

Wash the case good with Dawn and hot water, then lacquer thinner and if beat up use Satin Clear to make it look new again. Check your vacuum motors with brake bleeder or hook to a vacuum source to see it they work. 

I also add the mess wire over the cowl vent opeing to keep the mice out of the box and add the screen to the underside of the cowl vents to stop them there. You will also have to put stainless steel scrubber pads in the drains on the cowl to keep the critters out.

Use the rope caulk to seal up your heater box case.





aluminum causes constipation





 
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