Rebuilding a factory A/C unit - Done!

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Internals primered and painted...

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Thursday, red white and blue Santa (USPS) delivered my NOS switches and today I gave the cases a bath in cleaner/degreaser and hung them out to dry.

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I've searched far and wide for aftermarket or substitute materials for the foam gasketing that wraps around the damper doors, to no avail. While you can buy the rebuild kits for the heater only units, there's not enough stuff in those to do an A/C, maybe not even in two of them. At 68RGR's suggestion (thanks, Bill!) I decided to go with some foam rubber insulation for HVAC and plumbing applications. It stands up to home A/C and copper hot water lines so it should work with the heater core, evap core and dampers.

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Got all the internals prepped and ready to go back in and my case washed and ready. I have two things to deal with before reassembly. On the back case a big triangular piece broken out and on the front case, the place where the blower resistor melted the case. Looks like a little fiberglass work may be required. Never tried this before so it should be interesting.

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Randy - Before you junk the original fan resistor, please measure the resistance of each coil. Having accurate info will enable folks to get "modern" resistors to replace them.

Also, if you can figure out the current drawn for each speed, a wattage value can be calculated for both resistors/coils.

With those values, each coil can be replaced with something like this:



Or this:



IGNORE THE VALUES IN THE PHOTOS - The photos are only meant to show the types of resistors that might be used to replace the originals.

Finally got my "round TUIT"! Resistance values are .9 and 1.7 ohms. Does that give us enough information to select resistors? Thanks, Bill!

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Now that got the internals ready to go back inside, it's time to look to repair the busted front/back cases. Surfed the web looking for stuff and didn't see anything that struck me. Then was wandering around a the auto parts store and BINGO! Plastic mud flaps about the same thickness and with textured and smooth surfaces fro $12. Grabbed a set and and some plastic bond and started on the back housing first. Cleaned up the broken area and cut a piece to fit.

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Smeared a little glue on it to hold it place, taped up the gap and filled it with glue.

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Then peeled the tape off and grabbed my trust HF "dremel" and a grinding cone

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and cut a V groove all around and filled it with more glue.

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After that set up I glued the mounting ear back on that had broken off. While that's setting up I started working on the hole in the blower cavity where the resistor had melted it. Started with my REAL Dremel Multi Tool. Trimmed the inside where the melted plastic had rolled down.

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And then cut out the part on top. After cleaning up all the edges with my HF dremel, I cut another piece of the mud flap, bent it into a curve with a pair of pliers. Then spread glue all around the mating surface and clamped it in place. Gonna let that set up over night. Tomorrow I'll patch the top and start dressing everything up for paint.

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Got those holes patched this weekend. Good enough for flow and to be able to mount a new resistor.

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Now that the case is solid again, I began reassembly. Started by using the water line insulation and ArmaCell to insulate and cushion the top and bottom of the heater core. That actually worked really well and the heater core set back into the housing snugly.

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Clamped the heater core down and wrapped the damper door with the ArmaCell. That also seemed to work well as a substitute for the OEM foam type. The adhesive on the back of the ArmaCell is incredibly strong. Once you stick it on there it won't come off without ripping the foam. The foam itself is firm yet soft and feels like it will make a good seal. Once I got the damper in place I was able to get the baffle pan screwed in. With that in, I turned my attention to my evaporator core.

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As you can see, the fins had taken a beating. I just couldn't live with that, even though it probably would have been just fine. Discovered my large Bondo spreader was the perfect width to slide in between the fins. After spending quality time with needle nose pliers and my pocket knife, I got the worse spots folded back up and was able to slide the spreader through the fins. Came out pretty good.

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Since my vent registers are crappy and have a couple of broken vanes, I've got to figure out an alternative. Can't do much with the front housing until I have that nailed down. The vent damper is the first thing to go in and once it's in, it'll be difficult to maneuver installing the vents and the front dress panel.

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So here's the plan...

One perk of working in a fab shop is unlimited access to sheet metal and equipment. Cut a piece of .060 aluminum the size of the plastic bezel that was broken. 3.25" x 33". Bought these vent registers from Summit http://www.summitracing.com/parts/vta-4 ... /overview/ They were the largest cheap ones I could get close to the size of the old ones. I'll hand cut the rectangles, round the corners and drill the holes in the aluminum panel and screw it together with trim screws and flat nuts. Probably just silicone or glue the registers in place. I'll know better when I actually get my hands on them. Curious how the backs are configured, doesn't show a pic of the back side but looks like it has a duct flange that I might have to modify to be flat. Final step will be to finish the panel somehow. Paint, woodgrain, polish? Any suggestions?