Jim Smart
June 1, 2000

Step By Step

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Except for refrigerant and labor, Classic Auto Air’s in-dash A/C systems for ’67-’68 Mustangs and Cougars come complete with everything you need. CAA does a nice job of restoring factory assemblies. The heater core, evaporator, and condenser are new.
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Under the hood, you have a choice of either a factory Tecumseh/York compressor or a more efficient Sanden unit, as shown here as part of CAA’s conversion kit.
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Mustang radiator supports were factory stamped with provisions for air conditioning hoses. Drill two pilot holes (1/4-inch bit) to get started.
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Then use a rotary cutter to create two passages. A fine-tooth coping saw opens up the two holes into a single, oval opening.
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The new condenser is prepared for installation by attaching the receiver/dryer. Always use a wrench on both the condenser and the receiver tank. A thin film of grease at the fitting helps reduce corrosion and makes for an easier fit. Install the two bracket screws. Do not overtighten.
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The condenser is a perfect fit in our ’67 Mustang. Four hex-head sheetmetal screws secure the condenser to the radiator support.
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The sight-glass and high-pressure line come straight off the receiver/dryer and are routed through the radiator support.
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This foam seal slips over the two condenser lines and hides the transition through the radiator support.
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The high side line (larger of the two lines) is installed next. If you’re using the Sanden compressor, Classic Auto Air supplies a special line with a 90-degree bend at the compressor.
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The vacuum reservoir is next. The factory provides two indentation pilots (arrows) for drilling. Use a 3/8-inch drill bit for these holes which will provide an anchor point for the ’67-style vacuum reservoir. The ’68 reservoir is a coffee can–type affair that’s secured inside the fender well. A hole must be bored in the inner fender for the ’68.
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Here, we’re showing you the lay of the land with the engine removed. “A” is the provision for vacuum reservoir. “B” is for the heater fan motor on non-A/C Mustangs and Cougars. With air conditioning, this opening accommodates the refrigeration lines. “C” serves no purpose on a non-air car; with air conditioning, it accommodates the heater hoses. “D” is used for heater hoses with non-A/C applications. These are plugged when there’s air conditioning. “E” is two pilots for vacuum hoses (to the reservoir and hot water valve) which must be drilled to 3/8-inch. “F” is a pilot for the air-conditioning compressor lead, which must be drilled to 1/2 inch for the lead’s firewall seal.
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After drilling the two 3/8-inch holes for the vacuum hoses, we installed rubber grommets, available from any hardware store, to protect the hoses.
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Three holes (A) must be drilled to accommodate the big air handler brackets and studs under the dashboard. The factory has provided pilot indentations, which enable you to drill accurately. Use a 3/8-inch drill bit and go for it. Smaller 1/8-inch holes must be drilled (B) for the climate-control access plates.
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The air handler consists of a heater core and air-conditioning evaporator. Manipulate the unit carefully up under the instrument panel. Be careful because the fiberglass is easily damaged. Because visibility is virtually nil, you’re going to have to feel your way through this one until the bracket studs fit through the firewall. Have a helper temporarily secure the studs with nuts on the other side.
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The blower assembly is tricky to install and must be handled carefully. Enter from the right-hand side of the instrument panel and walk the blower into place. One attachment stud at the rear of the assembly penetrates the firewall. Another bracket ties the fan to an attachment point under the dash.
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The defroster outlets are next. This is a single-piece assembly that attaches to the four studs the previous defroster outlets left behind. Do not overtighten the nuts. This assembly is very fragile. Good news—Classic Auto Air will soon be reproducing this assembly for ’67-’68 Mustangs and Cougars.
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The air-conditioner/defrost-defuser assembly ties into the blower assembly and defroster duct.
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Installed, the air conditioner/defrost defuser should look like this. The adjustable, die-cast, air-conditioner outlet slips into the instrument panel and into the flexible duct.
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Because factory air conditioning is vacuum controlled and operated, all vacuum hoses must be installed correctly for proper operation. Classic Auto Air makes it easy with color-keyed vacuum hoses and a vacuum schematic for identification. Plug all of the vacuum hoses (per the schematic) into the climate-control panel.
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The climate-control panel has two plugs—one for the blower (three pin) and the other for compressor control (two pin). The three-speed blower switch is not a variable resistor unit, but a three-contact piece that routes the power through a three-way resistor to ground at the blower assembly. Compressor power passes from the fan switch to the compressor via a blower-door position switch and a thermostat. All switches must close to get power to the compressor clutch. The heat control cable (not shown here) must also be installed at this time.
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Don’t forget the evaporator drain in the air handler. A 1-inch hole must be bored in the floor to make way for the evaporator drain. This can be accomplished with an air-handler test-fit, fit checking the drain hose, marking the location, and drilling the hole.
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The air-conditioning ducts are next.
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The longer of the two ducts (arrow) is installed on the right-hand side.
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We suggest installing the 90-degree plastic elbows at the outlets first, then attaching the hoses.
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The heat deflector is attached with two push rivets (arrows).
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This is the expansion valve, which controls the rate of high-pressure, gas-refrigerant flow into the evaporator.
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The expansion valve (A) controls refrigerant flow by sensing the temperature of the low-pressure gas exiting the evaporator (B). When the temperature rises, the valve opens more, allowing more abundant refrigerant flow into the evaporator. When temperature drops, the valve closes, slowing the flow of refrigerant. When this valve is faulty, things can get either too warm or too cold. A frozen evaporator is typically the first clue of a faulty expansion valve. Thread this guy onto the low pressure side of the evaporator (smaller line).
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It’s time to install the climate-control seal on the engine-compartment side of the instrument panel. As with the rest of the system, there are pilot indentations that must be drilled with a 1/8-inch drill bit for sheetmetal screws. Install the rubber seal first, then the access plates.
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We suggest the use of rope caulk around the perimeter between the access plates and the firewall for added protection.
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The low-pressure gas line threads onto the evaporator as shown, and is then routed back toward the firewall and around to the suction (low) side of the compressor. The smaller high-pressure line is threaded onto the expansion valve and routed back toward the firewall and around the engine to the receiver/dryer. Make sure all fittings are tight. Perform a leak-check prior to servicing.
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The expansion valve and sensor bulb are wrapped with a funky, black-tar tape that serves as an insulator. It keeps the temperature constant and prevents line sweating.
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The Sanden compressor-conversion kit from Classic Auto Air is a simple conversion. Included in the kit is the compressor, adapter, belt, fastening hardware, and hose (not pictured).
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The Ford iron compressor mount is installed first.
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The Sanden compressor adapter bolts to the stock mount. Don’t tighten these bolts until you have adjusted compressor alignment with the pulleys.
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The Sanden compressor bolts to the adapter like this. We have installed our Sanden compressor with the fittings at 12 o’clock. But you can turn this compressor clockwise 45 degrees and have the fittings on the side.
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This simple bracket will tie the Sanden compressor to the factory compressor stiffener.
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The factory compressor stiffener is tied to the water pump and compressor bracket.
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Install the factory idler pulley next. We suggest a thin film of grease between the idler and the stiffener for easy adjustment.
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The Classic Auto Air Sanden compressor lines should be routed like this if your fittings are on top. If you roll the compressor clockwise, putting the fittings at 3 o’clock, line positioning is even easier.
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The completed Sanden compressor conversion should look like this.
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The drivebelt is routed like this, just like a stock installation.

Classic Mustangs are cool--unless you're stuck driving a non-A/C car in heavy, rush-hour traffic in July. As perspiration runs down your temples, it's easy to consider dumping that old Mustang (as one-time Ford boss Lee Iacocca would say). But dumping a prized vintage ride just isn't done by anyone who has any class, so we need to find a better solution for our hot-weather woes.

We decided air conditioning was necessary while sitting in traffic in a '65 Mustang on a Los Angeles freeway last summer. While L.A. summers are certainly no match for the heat and humidity of Atlanta, Houston, or Tampa, it does yield its share of discomfort when the mercury rises above 100. Our point? Unless you live in Alaska, you need air conditioning for your early Mustang.

Classic Auto Air has been designing and creating high-quality climate control systems for vintage Mustangs for more than two decades, offering either quality-restored, factory A/C systems or new aftermarket ones. For our '67 Mustang restomod project, we ordered the '67-'68 factory in-dash climate-control system.

Classic Auto Air's Al Sedita recommended the Sanden rotary/piston compressor for our installation because it weighs less than the factory York and Tecumseh piston units. What's more, it uses less power and saves fuel. CAA supplies a conversion kit with the Sanden compressor, which includes two '67-'68-style pressure hoses with Sanden-specific fittings, drivebelt, adapter, and all of the hardware needed for this bolt-on swap.

Installing '67-'68 factory in-dash A/C is challenging because of the limited space behind the instrument panel. It's a tough fit no matter how small your hands are. You must pay close attention to detail throughout the installation. You'll need to drill and bore holes that didn't exist with the standard heater system.

Electrically, you'll need to get power to the A/C system from a 20-amp circuit breaker. Power can originate at the ignition switch via the circuit breaker. If you're doing a '68, power can come from the accessory fuse terminal. Never power the climate-control system unprotected--always use a fuse or circuit breaker.

When it comes to refrigerants, you have two choices--R12 or R134a--especially with the Sanden compressor. R12 was the traditional refrigerant used in new vehicles until 1993, when it was phased out in favor of R134a, a newer refrigerant that is allegedly more environmentally friendly (ozone-safe) and definitely a whole lot cheaper to purchase these days at the local parts stores. R134a mandates a larger condenser, specific hoses and oil, and different seals, expansion valve, and compressor, so if you're installing a new Classic Auto Air air-conditioning system, we suggest the use of R134a as these systems were designed for this refrigerant. It's less expensive and readily available.

We're tackling a '67 Mustang that is on the home stretch of a restoration. As a result, we won't be showing you how to remove the heater assembly. But heater removal is easy. Drain the cooling system and cut the heater hoses on the engine side of the firewall. Remove the heater controls and disconnect the control cables. Remove the defroster outlets and hoses. Disconnect the blower motor in the engine compartment. Remove all of the heater attachment nuts on the engine side of the firewall. Remove the sheetmetal screw that secures the heater to the right-hand cowl-vent opening. The heater assembly is easily removed at this point.