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ac conversion

84burban on Mon February 16, 2009 8:45 PM User is offline

Year: 1984
Make: chev
Model: suburban
Engine Size: 5.7

My ac compressor clutch froze up and fried its the original r12 compressor and I am looking for info on how to convert to r134. I'm not an expert mechanic but i used to play one back in the late 1980' and 1990's so I know my way around a wrench. Can I just replace the compressor? I know thats to simple for my luck, any info would be great-thxs FRED


TRB on Mon February 16, 2009 9:34 PM User is offlineView users profile

Minimum requirements for converting a system to R134a.

If system has any refrigerant R12 left in the system it must be reclaimed by an approved recovery machine.

Accumulator/drier must be replaced with an R134a compatible replacement. Conversion fittings and label must be added to the system. Label should have the amount of R134a used and quantity and oil type listed. If vehicle is not equipped with a high pressure cut off switch it must be added. That is the required minimum! While complying with the EPA laws may not provide the best performance.

Flushing the system to remove the mineral oil and debris should also be done. R134a and mineral oil do not work well together so leaving it in the system with R134a is not recommended! O-rings should be replaced with either NBR or HNBR replacements. Adjustment of the pressure cycling switch may also be needed to achieve the best performance. In some cases an upgrade of the condenser may be required to achieve the original performance. In many cases the parallel flow condenser will not be available as a direct replacement. Using a universal parallel flow is an option. A new custom hose set would be needed for the different style fittings used on the various parallel flow condensers.

There are many different suggestions when charging a R12 system with R134a. System must be evacuated before starting the charging procedure. I suggest you start with about 70 percent of the original R12 charge and add an ounce at a time until vent and pressure readings reach the best available results. Remember it is easy to over charge a system with R134a so patience is important.

That's the standard response. If you have debris in the system you should read HECAT's flushing post and attachment.


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