| Blue Buddy
03-27-2009 20:13:12
67.220.41.155
20337
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| this is not as hard as people think,
- recover the old refrigerant, remove compressor and drain oil, remove reciever/drier
- blow out the lines from the compressor to the condensor, and the condensor, do NOT blow backward into the line going to the evaporator in the cab as that will likely plug the expansion valve, blowing the lines removes any oil that will come out
- install new reciever/drier with o-rings
- fill compressor to specification with PAG oil or ester oil, your choice ( usually ester for conversions)
- screw on the 134 adapter fittings
- vaccuum system for 20 to 30 minutes at high vaccuum with pump, and test for leaks
- charge system with R-134a to approxiamately 80% of the r-12 charge
- - if you have no factory numbers, use 12-16 oz of oil, and try 3.5lbs R-134a
- test run system, pressures on about a 70 degree day should be somewhere around 150 to 170 on high side, and 7 to 10 on low side,,,,some bubbles in sight glass are normal with 134a
- and this should work fine unless your in the south where it gets really hot, other things to do while your at it, clean the rad clean using lots of comprssed air, water does not do it, and open the cab roof and clean the evaporator fins, this can make a HUGE difference with system performance
>>any old oil left in system will tend to collect in low areas of sytem as it does not circulate, but it does not seem to bother
- note, older upright YORK compressors- some work ok, some will vibrate the belt and cause it to jump off, but only 1 in 20 as far as i have seen
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