Rebuilding a factory A/C unit - Done!

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Received one of my aftermarket vent registers today. It's cheap plastic but looks like it'll work. I'll have to check clearance for that duct mount to see if I need to cut it off. Looks like the tabs on the ends will snap in perfectly once I get the panel cut out.

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As I suspected, the duct on the back of the vent interfered with the operation of the AC/Defrost damper so I had to cut it off. It was just glued so a razor knife slit it just fine. Touched it up with a burr stone on my dremel. Got the holes drilled and vent holes cut on the panel. Now just waiting on my other register to come in and that'll be ready to install.

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One of my biggest worries was that my evaporator would leak so rigged up a pressure gauge, capped the lines and hooked the air to it. Pressured it up to almost 90 psi and found out that the expansion valve line had a leak. Glued and clamped a piece of rubber over it so I could test it. Pressured it back up and sunk it in a bucket of water. No leaks! I'll just replace the expansion valve and it should be good to go. Next, I'll install the AC/Defrost damper.

[sargentrs]

Wow! Can't believe it's been almost a month since I updated. Crappy weather and sick for 2 weeks really put a damper on my motivation. So I wrapped the defrost/AC damper with the ArmaCell. Worked out good. Then to put that damper back in. What a PITA! If you recall it has a split flange with a curled emboss. Tried for an hour to get it in there and then crimp the curl over the flange to no avail. Wound up closing up the split flange and barely rolling that curl over to hold it. Then put in the case, slid the rod in and tapped it all the way in. Took about 20 minutes but it's in now. Then turned my attention to the internal heat/AC damper and evaporator mounting plate.

[sargentrs]

Probably took me 15 minutes fiddling with that damper, referencing photos I took, till I finally figured out how it went back in. CRS (can't remember s--t) is a terrible disease that affects old farts like me. Wrapped it in ArmaCell, remounted the damper and screwed the evaporator mounting panel into the case. This week I received my new blower motor and wheel. I love getting NOS parts in their original packaging! Taped off the vents in the motor and sprayed with it with some primer and black epoxy for future rust prevention.

[sargentrs]

Prior to mounting the evaporator core, figured I better check out the mounting of my new switches. If you recall, I had a hard time finding an original switch but found the 69-'71 Mustang/Torino version fairly easily. Only difference is the bracket although it's riveted on. However, I failed to take into consideration the mounting bracket on the original switch and why it may be shaped so oddly. Well, now I know why. Guess I'm going to be fabbing up some kind of bracket to mount the Mustang switch.

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After scratching my head for a little while and digging through my buckets of "stuff", I found a sheet metal bracket that I thought would fit the bill. A little cutting with aviation shears and a little time on the bench grinder and my dremel, I came up with something that will work just fine. Sprayed a little primer and paint on it and waiting for it to dry before mounting.

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So, the bracket worked out pretty good. A quick shot of paint and it got screwed into place and the switch mounted. Also installed the joint damper linkage to make sure everything worked smoothly. Clean coat of vinyl/fabric paint on the rear case.

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Cleaned and shot a coat of the same paint on the front case. Decided to just shoot the front panel satin black. On the home stretch!

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Now where was I? Ok, before installing the evaporator I thought check out the operation of the everything again to refresh my memory. The inner blend door was not closing all the way. Figured out my new bracket was interfering so had to modify it a tad for clearance. Installed the blower wheel on the motor and mounted the motor in the backing plate.

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Added the screw to lock the motor from turning and turned my attention to the blower motor resistor. As you recall, I couldn't find a stock truck resistor so I bought one for a '69-'70 Torino. Terminal ends look the same and the resistor coils were a tad shorter in height but otherwise pretty much identical to the stock unit. A quick test fit showed me I had to notch a reinforcing rib but otherwise it was the same size and the screw holes lined up perfectly. Applied a strip of Armacell for a gasket and cut out the center for clearance.

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Screwed the resistor in place and mocked up the blower motor fan to check clearance. There's at least a 1/2" clearance between the blower wheel and the resistor coils so all is good. While mocking it up I discovered the purpose for that slot in the AC register/defrost duct damper door. There's a bracket sticking out of the back of the backing plate I had forgotten about so had to trim the Armacell gasket I had installed.

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Installed the blend door that's operated by the slide handle on the left front of the unit. This is what directs the air flow from to floor heat or closes it off for defrost/AC registers. It is held in by the screws from the front handle but also by a plastic plunger/grommet that keeps in lined up and sliding smoothly. If you're rebuilding you're unit, don't forget this! I didn't realize how it worked so pried mine loose and thought I broke the grommet. Fortunately it went back together just fine.

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Sprayed a final coat of satin black on the faceplate so gotta wait for that to dry. Selected some stainless socket head cap screws and flat nuts for installation. Almost ready to install the evap and close her back up. One more thing to figure out an install. I'm going to have to try to find something to fit into the case for a defrost duct hose. Haven't found a part number so probably going to improvise.

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So, after web surfing for days, I still didn't find anything suitable to fill these holes and provide a good mounting of my defrost ducts. So I went to my local auto parts store and still had no luck. Stopped by my local hardware store and while glancing down the PVC plumbing aisle, the little light bulb in my head went off. Picked up a 2-1/2" female thread to 2" female PVC adapter. Measured about 2-7/8" OD at the max on the threaded end and 2-3/8" OD on the smooth end. If it fit the hole, I could use a 2-1/2" defrost duct. Got it home and it just kissed the top of the box. However, it was just a tad too deep on the bottom to achieve a good seal with the defrost damper.