1987 Chevrolet Astro Van A/C Compressor

Does anyone know how to replace the A/C Compressor on the 1987 Chevrolet Astro van. The aircompressor has stopped working for the last two years and I would like to try to get this fixed. I took apart the dash board as well as several other parts of the top of the engine and still can't install the new air compressor.

If your AC does not work, it might not be the compressor. If some or all the freon has leaked out, the freon pressure switch will not allow the compressor to engage. A mechanic needs to find the leak, fix it, evacuate the system, (all the air and / or old freon sucked out) and install new refirgerant.
The R-12 freon that your truck used is not available now, and the system must be converted to R-134-A refrigerant, if more refrigerant is required.
So, even if you can change the compressor, there is still some specialised work to be done to the system.