308 A/C saga continues!

Well, I have the whole system back together and rebuilt. If anyone is thing ing of doing this, talk to me first, I have a couple of tips that can save you time and money. Anyway, I cannot find documentation on the specifications to charge my 83 308 QV? I have the OEM
compressor and I am using R12. How many pounds of Freon should I need?
What should my Hi/lo pressures be? Thanks!

P.S. I never got an answer to this question, my heater fan speed works in position 'I' but not 'II', any ideas?



Dom

 

You will need about 2-1/2 pounds or 40 ozs, which means that you will need at least four 12-oz R-12 cans if you buy them on eBay. I also have an '83 Mondial. I had to rebuild the Tecumseh A/C compressor and clutch bearings. Parts are almost impossible to get for this compressor and the York parts are not the same. Try Classic Air in Tampa, FL. I sent them the Receiver/Drier which they rebuild for only $70.00. Forget about an aftermarket replacement since it won't have the proper fittings. With the Receiver/Drier out, flush the system in order to free up and clean the Thermo Expansion Valve. You can use ordinary BrakeKleen Spray since it leaves no harmful residue or have your shop do it. Spray it into the hose that goes to the evaporator. A/C systems that are not used regularly often develop sticky expansion valves. Replacing that valve means removing the entire evaporator case under the dash - you don't even won't to think about doing that job. R-12 is so expensive that you don't want to attempt charging your system before ensuring that all else is in good shape. Also check the oil level in the compressor.

Now there is a sight glass on top of the Receiver/Drier; so if you are using R-12 you charge until the bubbles disappear and then add another 2 or 4 ozs. Of course the system has to be evacuated and checked for leaks, etc. If you convert to R-134A, then the sight glass must not be used as a means of indicating full charge! If you do, you will overcharge and possibly damage the system. Gauges are used to determine full charge. Flushing the system and rebuiding the Receiver/Drier are absolutely mandatory if converting to R-134A. The A/C compressor must also be flushed out and the Mineral-based oil replenished with Polyester Oil or PAG Oil. There are R-12 substitutes on the market (Freeze-12, Johnsens 12, etc.) that are blends that can be used in place of R-12. If you go that route, you charge to about 80%, which means that the sight glass cannot be used to indicate full charge; otherwise, the system will be overcharged and possible damage to the compressor will result.

 

The heater fan speed switch has 2 positions. the low speed position supplies power to a resistor on the fan motor housing. The other side of the resistor supplies power to the motor. Thus the resistor limits the current thru the motor.

This high speed switch position applies power directly to the motor.

I'd first pull the console & measure voltages at the switch to see if it's got an internal contact problem.

 

Not true. The fittings are a standard size pipe thread.