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Ford Air Conditioning
by Jerry Heep

Technical Editors:	William Fox
	Anonymous Ford Contact
	Iatt1234@aol.com (Curt)
	Vic Daku
E&G Editor:	Eric Ditwiler

Servicing Installing an External Water Valve The easiest place to install an External Heater water shut off valve is in the SOURCE water hose. This hose water source comes from the directly from the water pump. On my truck, the return water line already has a back flush connection. So the source line is “open” and ready. Select a position of the valve and cut the heater hose. Install two three-fourth inch nipple to one-half inch pipe adapters into each end of the valve. Install the valve into the hose as shown in the picture. With the handle as shown above, the water is turned off. Your spouse may complain that she cannot use the temperature control knob inside the truck to warm up the air coming from the heater. You have to open the valve to allow water to flow for heating control. Checking/replacing the Expansion Valve
1.  Once again we are assuming there is NO pressure in the system. Locate the inlet tube for the expansion radiator. Follow the tube toward the condenser. There should be part of the tube that looks like this:
2.  The tools are plastic. They have a slot cut into one side so that they can be opened and placed on the tube. Install a quick disconnect tool below the flanged part of the tube. Select one that has a hole of about the same diameter that matches the tube’s outside diameter. This was the BLUE tool for my truck.
3.  Pull up on the tool until the tool contacts the inside of the flange. Pull up slightly more and you will feel the tool give as it slides into the quick disconnect assembly.
4.  While holding upward pressure on the tool, wiggle and lift the flanged part of the hose away from the tool/mating tube.
5.  You should end up half of the connection looking like this:
6.  Look inside this tube. You should see the top of the expansion valve inside. Using a pair of needle nose pliers, reach down and grab the top of the valve. Pull the valve out. It is being held in place by two O-rings and maybe dirt and grime to act as glue. The white part was deep inside the tube. Notice the arrow formed into the white plastic just below the O-rings. This arrow shows refrigerant flow direction. If the valve was reversed, it is easily plugged by dirt and grime, since the larger screen is on the wrong side of the flow.
7.  If you are just going to clean the valve, blow off the dirt and grime from the screens. Check out the two O-rings on the valve. If they are flattened or broken, you might consider replacing the valve. Make sure the orifices are open. Take the old valve with you to the parts store so that you can show the parts dud what it looks like when he frowns at the words “Air Conditioner Expansion valve for a Ford Diesel truck.” If you get your valve from the same place where you buy your rebuilt compressors, you will never get the frown. 8.  When all is clean, install the valve, white side down, into the tube. Press on the RED end until the O-rings seat. To make it go easier, coat the O-rings with PAG oil before assembly. 9.  Now look over the matching hose connection. There are two standard O-rings on this end also. Clean off the end and inspect the rings. It is best if you just go ahead and replace these rings. Before installing the hose, coat the O-rings with clean PAG oil. 10.  Place the hose fitting back into the matching fitting. Press down on the hose until the quick disconnect assembly receives the hose. 11.  Make sure the connection is tight (the connection will rotate, but don’t force it.) You are done. 12.  By the way, there was a member that mentioned that he installed a newer expansion valve – one out of a new truck. Designed to operate with R-134a, the new valve was BLUE instead of RED, like mine. It seems that RED is the color for R-12 valves. These blue R134a valve have larger orifices, allowing more R134a flow and as a result, gives cooler air. 13.  There are also VOV (For Variable Orifice Valve.) The above shows a FOV (Fixed Orifice Valve.)  The VOV has the added advantage of better cooling at lower compressor speeds (idle.) These valves are pressure operated and spring loaded. I’ve seen prices below 30 dollars for a VOV and a tenth of that for a FOV. It has been reported from test sites that there are less compressor failures with a VOV when compared to a FOV.

Replacing the Compressor

1. Turn off the motor and allow cooling time so that the radiator does not burn your skin.
2. Remove the clutch control wires that are located between the pulley and the compressor, centered between the two. The connector can be removed by wiggling it while applying upward force. Do not pull on the wires. Use a small screwdriver to pry the connector up on both sides. You may have to pinch the outside of the connector to release hold down clips. If you have a clutch that uses the single wire, pull apart the quick disconnect inline connector.
3. If you have a serpentine belt, do your breaker bar thing and loosen and remove the belt. Now sit back and wait for us older truck guys to finish with our belts. We’ll meet down at step 8.
4. Using a socket of the proper size, remove the top bolt on the compressor that that is on the front support bracket. This bracket is parallel to the fan belt(s). The bracket is just a plate of steel that connects to a hunk of metal that acts as a spacer. There are two long bolts that hold the plate and spacer sandwich onto the block. There is one short bolt that connects into the spacer hunk. This is a pivot bolt.
5. The two long bolts are preventing the rear plate from pivoting. Loosen these bolts. The pivot bolt just above the long bolts needs to be loosened.
6.   Now you should be able to push the compressor toward the center of the motor. This gives you slack to remove the air compressor belt.
7. If you are repairing a busted R-12 compressor and have a good charge of R-12 still, you can replace the compressor without loosing much R-12. Notice the valves on the two compressor hoses. If these valves are closed, you can remove the manifold while retaining the R-12 in the rest of the system.
8. Ok, serpentine guys, wake up. Using the correct sized tube wrench and a Crescent wrench to hold the manifold, loosen the high-pressure hose fitting. Warning: you must use TWO wrenches to remove this hose. If you do not counter-support the manifold with the Crescent wrench, you can crack or break the manifold tube. If you do break it, you will have to buy another. Also note: these fittings can be very hard to separate. They sometimes feel like they are wielded together. Rust can make them very hard to break apart. If worse comes to worse, you might consider removing the two small bolts holding the manifold to the compressor. This will allow you to remove the high pressure hose completely and support the manifold in a bench vise – yes they get that hard to separate. If there is R134a in the system, make sure you are in an open area. This gas, while not toxic, will displace oxygen – it can smother you as fast as putting a plastic bag over your head. If there is R-12 in the system, you MUST recycle it. Watch out for blowing oil. You may want to put a shop towel over the fitting to keep the oil from spraying out all over the place. A small cup to catch the oil from the towel will keep your motor finger licking clean. Once all R-134a is out, remove the fitting from the compressor. Look at the hose end and confirm the existence of the O-ring that is used to seal the hose/compressor connection. If there is no O-ring, look inside the manifold for it. If the O-ring is flattened or brittle, consider replacing it. New ones are usually green. Older ones are black.
9.   Now do the suction side hose in the same manner as the high-pressure side hose. This hose may be even harder to come off as the first hose was. Magic words seem to help. Don’t forget to check for the O-ring state.
10. Once both hoses are off, remove the two remaining bolts holding the compressor to the front plate. There are two lower ones.
11. Remove the two bolts holding the compressor to the rear support plate. The compressor is now free of the bracket.
12. Remove the compressor from your truck and move it to a bench vise. Capture the two front or rear bolt tabs with the bench vise to hold in place.
13. Remove the two smaller bolts that hold the manifold onto the compressor and remove the manifold. Each manifolds has two O-rings. If they are brittle or flattened, consider replacing them with new ones. The new ones will be red in color.  A rebuilt compressor can cost you around 150 to 200 bucks. A new compressor can cost two to three times that much. Maybe even higher. It’s your dollar. A rebuilt Ford Compressor will have a clutch on it. There is a core charge for your old compressor and clutch. I have never been disappointed with a rebuilt unit. I usually go to the same compressor supplier that professional mechanics use. Ask around. If you buy a compressor, don’t be surprised that it does not have manifolds on it. Don’t let loose of your core until you have confirmed that none of the core parts are needed for the rebuilt compressor. Bring your old compressor with you when you go to pick up your “new” one. Compare the new one with the old one. If one does not look like a cleaner twin brother of the old one, find out why.
14. There will be two plates that are protecting and covering the inlet the outlet portholes on the “new” compressor. Remove the screws holding these plates to the new compressor and transfer the plates to the core. Remove the new compressor from the cardboard box and put it on the bench.  Put the core in the compressor box and go get your deposit back. Don’t forget to get new O-rings for the manifolds and PAG oil for the new compressor while you are there.
15. When you come back with the O-rings, install the pressure manifold, using new O-rings, if you have them. Before installing the suction manifold, fill the compressor with PAG oil. According to the specs on the Ford compressor I bought for my ‘87, it needed 15 ounces of PAG oil. Slowly pour the oil into the compressor at the two suction ports while turning the compressor clockwise with your hand. Don’t forget, you must turn the compressor’s center shaft to rotate the compressor’s internal vanes. Turning the outside pulley on the clutch does nothing. Do not attempt to lubricate the pump while it is under motor power – the belt spins too fast and can easily make that new compressor a boat anchor. Once the oil is in, attach the suction manifold.
16.   Install the new compressor onto the bracket in the reverse manner it was removed.
17. You can tighten the four lower mounting bolts that are holding the compressor onto the rear and front plates. Do not tighten any other bolts until step 19. You serpentine belt guys can tighten the compressor down and do your belt thing. Wait for us at step 20.
18. Loop the compressor belt around the crankshaft pulley (lower one) and the water pump pulley (upper one.) Loop the belt around the compressor pulley.
19. nsert a piece of wood between the compressor bracket and the compressor. This is on the “motor” side of the compressor. Using a long screwdriver or your favorite pry bar, insert the bar between the bracket and the wood. Apply clockwise force on the pry bar and rotate the compressor away from the motor. This will apply tension on the belt. With your third hand, tighten one of the lower pivot bolts while maintaining pressure on the pry bar. This one bolt will hold the tension on the belt long enough to go to the next step.
20. Tighten all front and rear bolts.
21. Connect the clutch electrical cable.

Replacing the drier/accumulator

1. If there is a pressure switch on the side of the drier, remove the connector from the back of the switch.
2. Using a wrench, remove the switch from the old drier and connect it to the matching location on the new drier.
3. Remove the compressor hose (suction side) from the drier. This is a very large nut on the hose – I needed a 1¼-inch open-end wrench for my truck. You will need another wrench to hold the drier side. This connection may be very hard to break. We are assuming the system is already bled down.
4. Remove the expansion radiator connection to the drier. This connection may be even more difficult than the other. You may need to soak the connection in “Liquid Wrench.”
5.   Remove the drier and check the two O-rings on the cable ends. Replace if broken or brittle.
6. Position the new drier and attach and tighten the Air Handler connection. Don’t forget to use two wrenches and use proper counter-torque to prevent damaging the new drier or the air handler.
7. Attach and tighten the compressor hose.
8. Connect the new pressure switch to the side of the drier, if you have one.
9. Connect the pressure switch cable to the socket at the base of the switch.

Converting to R-134a

1. If you buy a conversion kit from Auto Zone or Wal-Mart, what you will be receiving is two tubes of conversion oil, two adapters, a label. The instructions are on back of the board. All this will cost you 17 to 30 bucks, depending on where you get it. The oil supplied is used to “convert” R-12 oil into something that is compatible with R-134a. The tubes the oil comes in are specially designed to allow you to inject the oil into the system. You then mount the adapters onto the old fittings and follow instructions. You will need a hose kit that allows you to fill the system from the 12 ounce bottles of R-134A. That old one you used for R-12 ain’t gonna get it any more. Go to step 7.
2.   If you are converting over your system after a compressor rebuild, you might as well avoid the kit and buy the R-134a parts from the same dealer as handled your compressor. Get a package of 10 O-Rings, at least 4 bottles (48 ounces—3 pounds) of R-134a, a low pressure and a high-pressure adapter. These adapters convert R-12 fittings into R-134a fittings. The high-pressure adapter is not really needed unless you have a full set of professional air conditioner gauges. You will need 12 to 16 ounces of PAG oil. Make sure the PAG packages states that it is useable in R-134a systems. There are “Ester” oils that are meant for GM air conditioning systems. You don’t want that stuff. The counter guy that gave you the compressor can look up the fill numbers for you. If the budget allows it, you might look at getting a new drier (about 50 bucks.) If you want to change it all, get an expansion valve also.
3. Remove the OLD R-12 oil. Unless you use the kit that converts the old R-12 oil into something that R134a can handle, you got to get the old stuff out. The best way I’ve found to do this is to blow out the hoses and all components with compressed air. Do not blow out the drier with standard compressed air. All you will be doing is injecting moisture into a component that doesn’t need it or want it. If you have a vacuum pump, suck the oil out.
4. Pour in the PAG oil as described in “Replacing the Compressor” above.
5. Mount the compressor and all hoses.
6. Mount the Drier, as described above.
7. Mount the R-134a adapters to the Schrader values. The adapters have force-activated epoxy on the threads. You must insure that the Schrader valves are tongue licking clean (carburetor cleaner does wonders) before attaching the adapters. Once you screw on the adapters, leave them alone. They will wield themselves onto the valves quite rapidly. The Low-pressure side and the high-pressure side adapters are different sizes. The High pressure Schrader valve is smaller than the valve on the suction side. The high-pressure adapter will not fit your R-134a fill hose.
8. Clean or replace the expansion valve as described above.
9. If there is any R-12 in the system, you need to have it removed and recycled by a licensed technician.
10. I have yet to pull a vacuum on any of my R-134A conversions and have had excellent results. BUT – you run the very real risk of leaving moist air in the lines. This moisture can overpower the drier and freeze the small orifices of the expansion valve. If this happens, you could blow a seal in your brand new compressor.
11. If you have a vacuum pump, connect it to the system and pull the system down for at least 30 minutes. If no pump, you might be able to get a local A/C shop to pull the vacuum for you. Install a 12-ounce container of R-134A onto the fill hose adapter and puncture the seal as instructed by the kit. The female outlet side of the fill kit should not allow product to escape. The refrigerant side of the hose is shown at the left.
12. Install the outlet fitting onto the SUCTION side of the compressor. This end of the hose is shown below. This is the side that has the hose running to the drier. If the hose goes to the Condenser in front of the radiator, it is the HIGH PRESSURE side. In theory, you can’t confuse the two because the connectors are different sizes and the connector for your fill hose will not fit the high-pressure adapter. The compressor will start to cycle as that first bottle is ingested and the increased pressure activates the switch.
13. Turn the bottle of product upside down for liquid fill, right side up for gas fill. For the first three bottles, I do liquid. By the time the second bottle is ingested, the compressor is running full time now. For that last bottle, I do gas and increase the RPM of the motor. You will know refrigerant is moving since the bottle and fittings get quite cool. When the bottle is no longer cool to the touch, it is empty.
14. DO NOT OVERFILL. Use no more R-134a as you would R-12. My truck took 48 ounces (3 Pounds). Find out how much your truck will need. If you overfill, you could blow a compressor seal or other expensive parts. An OEM suction hose will set you back 40 to 50 bucks. The drier cost about the same. The R134a cost me 4 to 6 bucks per bottle. The only cheap air conditioning part is the O-rings. About a dime a piece. Those never blow up. Only something expensive will blow up. Murphy guaranteed that with his Laws.
15. You must disconnect the hose from the suction adapter BEFORE you change bottles. If you remove the bottle before you disconnect the female adapter, the system will drain out through the bottle end. You can store a partial bottle of R134a while it is connected to a fill hose, so long as the bottle is screwed tight against the internal rubber gasket. There must be enough refrigerant in the bottle to keep the pressure valve closed at the fill hose female adapter. If there is liquid in the bottle there will be enough pressure to hold the valve closed.
16. There should now be cool, R-134a refrigerated air coming out of the vents. Enjoy.

References:
The author’s and technical editors experiences and knowledge.
Questions and answers can be found in several forums.

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