[ddsmith]

This is the third and hopefully last installment of the installation. So far we've got most of the inside work accomplished and a big chunk of the outside work done. The light at the end of the tunnel is near. It's time to run the A/C hoses to get the freon side of the system closed up. The kit comes with a TXV(thermostatic expansion valve) that needs to be installed on the bottom left(looking from the front of the truck) line coming through the firewall. Again you need to use the appropriate lubricated o-ring when installing the valve. The top of the valve has a dome on it with a line coming out of it. This is the sensing line and needs to be install on the upper line. There is a special clip that comes with the kit to allow attachment. The important part of placing this sensing tube is that you take care with it and gently bend it so the pigtail looking part is parallel with the upper tube and then clip it to the upper tube. The next thing to do is take the refrigeration tape(sort of a sticky black spongy tape and wrap the clip and upper tube and continue wrapping the sensing line all the way back to the dome of the TXV. When this is complete you'll have three refrigeration hoses that need installed. One hose is installed between the liquid line outlet of the condenser(hi pressure liquid line) and runs to the TXV you just installed.
Caution: The compressor will probably have some residual pressure when removing the caps for hose install and will come with oil already installed. The A/C compressor can mount at the upright or 90 degree position. If you mount it at the 90 degree position. The discharge port will allow some oil to be pushed out of the compressor.You may chose to keep both fittings pointing upward when installing the hose to retain the oil in the compressor. One hose runs from the upper left line coming through the firewall(lp gas line) and goes to the inlet of the compressor. One hose gets installed between the compressor discharge and the condenser(hp gas). The ends of the hoses are all o-ring sealed. Ensure that the proper countertorque is applied(use two wrenches and don't overtorque) when putting together any of the A/C fittings in the kit or you will be setting yourself up for problems.
Time to install the heater hoses. I purchased a long piece(I think 10') of 5/8" heater hose from the hardware store. Just make sure you have enough. You'll also need a bunch(at least six) of hose clamps for this heater hose. The hard part of installing the heater hoses was fitting the adapter for the water pump. It was originally 3/4" hose adapter. When I tried to put in a 5/8" hose adapter it was to wide at the nut portion of the adapter to thread in and provide full contact. The nut portion had interference with the water pump body. I ended up purchasing a short section of pipe and a double female connector to move the nut portion out away from the water pump body. Two valves are supplied with the kit. One valve is a manual shutoff valve and one is a cable operated valve. The manual valve gets installed in the hose installed from the upper right pipe coming through the firewall and goes to the water pump adapter we just discussed. You select the location along the hose. The second valve is more tricky when it comes to location of installation. I routed a hose from the bottom right pipe coming through the firewall and it runs to the fitting on the intake manifold by the A/C bracket. When the hose is run then you can move back to the inside. Don't worry we'll get back to that cable operated valve soon.
You can start off by reinstalling the radio. Take care to ensure the defrost/ac hoses don't get torn when putting the radio in. Reinstall the ashtray. The next part is a bit of a pain to get right so be patient. There are two cables supplied with the kit. The longer cable gets attached to the bottom lever and routes through the firewall to the engine compartment. This is the cable that operates the heater control valve. My installation was a A/C cab and I already had a opening where an original cable came through the firewall, so I just routed the new cable right where the old one went through the firewall. If you have a none A/C cab you may have a similar grommet to route the cable through or you'll have to improvise. The cables are held on the pins with some small push nut type fasteners. The ones supplied with the kit just made me angry so I bought a small assortment at the hardware store to prevent further frustration. The important part about all these cables are that they are adjustable by changing the location that the metal clips hook on to the cable. In my case, I had to mess with both cables on the end where it attaches to the control unit to allow full motion of both levers. The short cable gets routed from the middle lever pin to the defrost damper on the upper left hand side of the A/C unit. I would recommend ensuring that the middle and lower levers have full travel after tightening the attaching screws at the A/C control panel. After you verified this you can install the short cable to the defrost damper and then tighten the clamping screw down at the bracket on the left side of the A/C unit when the cable will provide full open and close position of the damper. The bottom lever should be placed in the cold position. You should hear the microswitch click when you are sliding the lever toward the cold position. Now we move back outside. The cable gets installed in the hose we left alone earlier. The key point here is that the cable needs to be routed to prevent to tight a radius on turns. In my picture you'll see I have a loop to provide this. Once routing is determined then you can figure out where to cut that new hose you installed earlier so the cable operated valve can be installed. When the valve has been installed then you'll need to adjust the clamp screw on the cable operated valve to allow full valve travel. Test the full throw of both middle and lower levers to ensure proper operation. Connect the wire harness to the A/C control panel and install the panel in the dash. Recheck for proper operation of the middle and lower levers. Adjust as necessary. The wiring of the system is very straight forward so I'll let you figure it out. Just ensure the green wire going to the compressor is not hooked up until your ready to charge the system. You need to have the manual heater valve and the cable operated valve open when you first start the engine. This provides coolant into the heater section of the evap/heater and prevents freeze-up of the heater coil. Make sure the A/C compressor is mounted tight and the belt tensioned properly. The A/C compressor can mount at the upright or 90 degree position. If you mount it at the 90 degree position, which I did, oil may come out of the hi pressure gage connection when the system is charged, which it did. Hopefully your other belts are new also. Unfortunately, my alternator belt is not new because my new alternator belt wound up on the A/C compressor. Now you can take the truck to an A/C shop or attempt the charge on your own. I don't recommend this unless your willing to spend some cash to buy a R-134A gage set and a vacuum pump which is capable of drawing a deep vacuum(greater than 29.0"). The point of the deep vacuum is to remove moisture from the system. All the lines were open so this should be done. This also allows you to check for leaks in the system. This is a must if you don't want to be charging all the time. Also if you take it to a shop, make sure they evacuate the system and hold it at least 30 mins. The longer the better. The charge is more touchy on the R-134A system. Overcharging should be avoided. Don't forget to shut the manual and cable operated heater valves before charging the A/C system. Place the control panel lower lever in the full cold position and connect the wire at the A/C compressor. Run the fan on Hi Speed with the doors and windows shut. This system runs a relatively low suction pressure so don't be suprised when the suction pressure is running around 20#. The important part is charging to get the air outlet temperature cold and stopping when the system is functioning correctly. Well I think this wraps up the Old Air A/C system installation. Good luck and enjoy the fun.

Don