First time attempt at a/c recharge

[ford_nut]

Hello all
I hope that someone can offer some insight. I have a 91 EX 4.0 with an A/C the blows warm. The clutch cycles but the car does not cool. Last year I took the car to a mechanic and he installed a used compressor as the old one was burned out and he recharged with Freeze 12. NO other parts were replaced. Total cost $375.00. Now the A/C doesnt work. I decided to buy a new robinair gauge set and vacuum pump to do the job myself. I have a complete freeze 12 kit (3 cans refrigerant) Plus 1 can oil charge. Looking over the the system, I notice that there is 1 line (the one that has this round canister in the middle), that has this black oily sludge on it. The oil sludge looks to be right at the inlet and outlet of that round canister thing. Is this normal??
Everyone that I talk to tells me NOT to mess with A/C and that I should have saved my money on the tools (I also bought a O-Ring springlock removal tool and a kit of those green O-rings).

The freeze-12 kit that I bought has adapter fittings that need to be used to charge the system. Do I use the blue adapter fitting on the manifold set to adapt the freeze-12 hose to the yellow charging port? I also hear of purging the line of air. How do I do this? Keep the line cracked at the gauge while I open the can then tighten?
As for the oil charge in the can, charge can upside down as a liquid in the HIGH side WITH THE ENGINE OFF? Someone told me to not put liquid in the low side, only gas.
I am getting really frustrated here and I am about ready to abandon this project altogether as I am now having second thoughts!
Any help will be greatly appreciated!
Thanks in advance
Ben

 

[Glacier991]

Ben, I suggest you start by reading the sticky thread "Recharging your AC A to Z" at the top. Come back with any remaining questions.

 

[Glacier991]

PS that can "thing" is a muffler and a bear to clean out, I often just replace it on a complete rebuild.

PS. Remember to replace the accumulator and at least check the orifice tube. Flushing the condesnor is a good idea as well.

 

[jo150612]

where is the low pressure point for a/c 2001 sports trac?

 

[Glacier991]

On the accumulator. The nice thing on 134 systems is taht the low side connector cannot be put on the high side. (smart idea). Passenger side near the firewall is where it (accumulator) sits.

 

[ma96782]

Air Conditioner: How does it work?

http://www.explorerforum.com/forums/showthread.php?t=160498

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How to use the manifold set:

http://www.autoclimas.com/Refrigerant charge.php

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Evacuate and Charging Procedure.

Attach a/c manifold gauges to the vehicle. Make sure you attach the correct hose to the proper service port. This is very important to prevent personal injury! Attach center (Yellow Hose) to a UL approved a/c vacuum pump. Open both of the dials on you’re a/c manifold gauge set. This will allow the system to be evacuated through both the low and hide side of the system. Turn your approved vacuum pump on starting the evacuation process. 30 minutes usually will be enough time. If vacuum pump has ballast read the owners manual concerning this option.

When system has achieved a state of 29.9 hg’s of vacuum close both dials on the a/c gauge set. You may loose up to 1 hg for every 1000 feet above sea level depending on the capacity and quality of pump. At this point wait 5 to 10 minutes letting the vacuum boil off any moisture trapped in the refrigerant oil. This is also a good time to watch and see if vacuum has returned to a zero state. If so you need to check for leaks in the system. Assuming the system is holding a vacuum after letting the moisture boil off repeat the evacuation procedure again. This process may need to be done a few times before all moisture has been removed and you see no degradation in vacuum after closing both dials for 5 to 10 minutes.

With both dials closed remove the center charging hose attached to the vacuum pump and connect it to either a can tap and refrigerant or 30lbs refrigerant cylinder. Open the valve on either the can tap or 30lbs cylinder allowing refrigerant into the charging hose. With refrigerant in the charging hose slowly crack this hose at the manifold gauge bleeding off any air that may have gotten trapped when moving from the vacuum pump to the refrigerant source. Only the slightest amount of refrigerant should be released in this process so be sure to tighten the charging line quickly!

Open only the low side dial on you’re a/c gauges allowing refrigerant to flow into the system. Again I stress the high side must be closed or you may cause personal injury to yourself or others! Start vehicle and turn on the a/c system with blower on the highest speed. In some cases if the compressor clutch has not engaged you may need to by pass the low pressure cut out/cycling switch. Refrigerant should be charged as a gas but in some cases it may be necessary to charge as a liquid. Be careful not to slug the compressor with liquid refrigerant! Charge system to OEM amounts and pressures if you are using the refrigerant the system was designed for. If vehicle is has been or is being converted start with about 60 percent of the original charging amount. After getting 60 percent of the original charge slowly add an ounce at a time until you reach the best possible vent temperature and pressure readings. If you do not know what your systems operating pressures are you can use the 2.2 x the ambient temperature as a guide. This should only be used as a guide as many systems will need more or less refrigerant to achieve proper cooling.

Having a weak fan clutch or an inoperative electric fan will cause system pressures to be incorrect. So make sure these components are working correctly before charging a system!

In lower ambient climates, doors and or windows of the vehicle maybe required to be open to achieve proper cooling when charging the a/c system.

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http://www.stu-offroad.com/engine/ac/ac-1.htm


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First, you still have air in the system because you must use a separate vacuum pump and its not evacuated completely down until you get to 29in. vacuum. Running the compresser with out r134a is like running your engine without oil.
Second, If you didnt remove any oil you shouldnt add any. Over oiling reduces the efficiency of the system. You must drain the compresser of oil and put back the same amount.
Third, Overcharging is murder on the compresser and will soon fail.
Fourth, The proper way to check the system is to check the ambent temp chart and run the fan on high cooling at max and no recirculate. With a long stemmed thermostat check the outlet temp at the RH passanger outlet with engine at idle for at least 10 minutes running and compair it with the chart temp.
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Aloha, Mark

PS.....the Haynes book says ('91 Ford Explorer)........at ambient air temp of 80 degrees F, hi velocity fan in front of the condenser, 1500 RPM.........22-50 low side and 160-250 high side pressure. Capacities: oil 7 oz and R-12 2.0 lbs (32 oz).

BTW....my '94 Explorer (factory R-134a) used a blue orifice tube.