That sounds loud !  You got a stethescope?  It's a possiblity that its the idler bearing.  If you don't have a stethescope,  you could pull your a/c belt off and spin the idler pulley to see if it feels rough.

 

Here is a video with a sound very similar to yours youtube

Edited April 10, 20168 yr by hr369

ok i looked through some of my a/c stuff and found this.  It's 1/2" 20 pitch. 

pretty sure the pulley bearing is ok, when I was checking over things, I removed the belt and gave it a spin, was smooth and quiet.

 If the idler bearing is OK use a stethoscope or a short piece of garden hose to one ear and listen to the AC clutch. When they start to go bad they can make a lot of noise.

 

second that on the garden hose if you don't have a stethescope. Those bearings are pretty sneaky as you can see in that youtube video i gave you a link to

@hr369 where have you been?  Hope all is well.  I was googling around and found your diagram and thought I'd ask if you might have some a/c parts you would sale.

Would you have a high side switch for a '77

Thanks for any reply, help.  Cliff

On 4/6/2018 at 4:44 AM, siteunseen said:

Cliff, i looked through my misc ac box and didn't see one.  I changed mine out to a zx drier over 10 years ago when i ripped out the aftermarket ac and put in factory nissan stuff.  If you pull that switch out of there you really should replace the drier and its damn near impossible to find a 77 anymore. Just checked msa and they want 339 for one wow!  Probably a rebuilt unit.

I converted over to a zx drier because they're much easier to replace. You could get a generic binary high and low pressure cut out switch and see if the threads are the same in the 77 drier if you don't plan on replacing or luck out and find one.  They're fairly cheap. https://www.ebay.com/i/311040852372?chn=ps&dispItem=1

Mine was a generic normally closed binary and i plugged directly into the stock a/c cutoff switch plug.

 

 

Thank you! 

Appreciate your time looking and giving an alternate work around. Cliff

You see this Jim? @S30Driver  maybe we can get some cold air in our '77s? There's a couple at that junkyard. Send me a pm about what you think.

Edited April 10, 20186 yr by siteunseen