A/C Rebuild Kit - 1977 Trans Am?

[Lantzwl]

Hi, I wanted to get my A/C working again on my 1977 T/A with a 400 automatic car.

I am sure it needs a new compressor, but I don't know what else, as it has been so many years since I have had it working.

Do you have any suggestions on how I should proceed and the best parts route?

If I'm lucky, do I purchase new or rebuilt or maybe old junkyard parts?

Thank you for any help or ideas.

 

[Aus78Formula]

New parts for these now exist, but this is not always true.

Hoses are unsuitable if exposed to elements and atmosphere or swapped to R134A, especially decades later.

Hard lines are okay; they clean and flush and don't soak up crud. A6 compressors and variations are common, so be aware that since they have been used for decades, the rear manifold threaded stud and bracket threads can be imperial or metric before you tighten them.

The condenser and evaporator are bulletproof, but a leak-down vacuum test will tell the story.

Both can be replaced with new if you have access.

Drier is a little trickier; these are a service part and can't be reused if left open to air, or the original type is useless.

New units work with either refrigerant; the originals were inefficient, and silica was unsuitable.

The challenge's other part is locating all the original Pontiac 400 AC brackets, especially if the previous owner removed and tossed them.

Most are used only, so reusing any you find is fine.

You can now get parallel-flow condensers that are more suitable for R134a cooling than stock, and you can also change the orifice tube from stock to variable.

Green o-rings all around, pressure switches are a bonus if you find the original GM with an adjustable screw for tweaking cut-off points for max cooling.

Sealed units are just set to a general setting for everyone.