Ref. 75 F-150, 390, factory air.
When we bought it in April, the compressor shook and sounded like it was
ready to blow up. I had it evacuated. I installed a new receiver/dryer and
a rebuilt compressor (less clutch) from Advance Auto Parts. The local
a.c. shop evacuated the system and installed 2.4lb of 134A. for $80.
(Did I say the system was converted to 134A by an a.c. shop in 97.)
The replacement compressor shook and rattled just like the original.
The shop evacuated the system again. I exchanged the compressor under
warranty, installed it, had it evacuated and charged with 2.4lb of 134A for $50.
I get the same shakes and rattles as the original compressor.
W H Y ?
The compressor is installed upright, not on it's side.

 

is the pulley bent? or f'ed up?

 

Are all of the brackets, including the support rod that goes to the exhaust manifold in place and tight.
Vibration is one of my pet peeves with the York style compressor, that's one of the reasons I went with a Sanden.

 

Also, this setup has two idler pulleys, the one that's used to tighten the belt then a second that is located kinda down between the water pump and power steering pump. This one is fixed, not adjustable. It's sole purpose is to keep the belt from vibrating and causing problems. Without it the span between the compressor and crank pulley is way too long and allows the belt to vibrate really bad.

 

When the clutch is not engaged, it is smooth as silk. All of the bolts are tight.
Ref. the rod. This 390 has headers. Therefore no rod. Our 66 T-Bird has the rod. Any suggestions?
The non adjustable pulley is in place.

 

Here's a diagram of the factory brackets. Note there are two 8678 idler pulleys, one adjustable, one fixed. Also you can see the 2889 support bracket, quite often, this is missing.

 

If it were mine, I'd bite the bullet and convert to a Sanden style compressor. Light, smooth, efficient and quite.
And they're cheaper than York. A rebuilt York is usually $200 or more. A new Sanden style is around $185 including clutch and pulley.
The conversion is not complicated at all.
Here is a link to my conversion thread, this was also a 390.
https://www.ford-trucks.com/forums/1...onversion.html

 

Thanks for the diagram. I printed it. I see the rod. I hunch that it sets on the ext. man.
tapped hole. What are the possibilities of a modified rod that bolts to the head
via a header bolt? Could I shorten THE rod, squish the end and drill a hole that lines
up with a header bolt?

 

You're correct, the rod attaches to the exhaust manifold at the threaded hole about midway on the manifold.
I don't see why you couldn't modify the support and attach it to the header bolts.