When I start my 96 and turn the A/C to high and start to accelerate it squeels like mad. If I turn it down to normal A/C it's ok. I recovered the charge (down almost 1/2lb but could not find any leaks) last year, put in a little oil and recharged the system to Ford spec...It was ok for the rest of the season. I tried a new A/C clutch - didn't help. My A/C is nice and cold, down to 4*C leaving the dash but the squeeling on high drives me nuts....Any idea's?? I have another pump here from a 94 Mustang GT, looks to be the same so maybe I'll swap them and try that?

 

Blindly swapping parts is the WORST way to fix anything, especially things like A/C compressors. Never open the refrigerant system unless you absolutely MUST.

Did you ever set the gap on the clutch?

 

I do A/C at work all the time, I know what I'm doing as far as contamination and etc....The system was vacuumed before it was recharged and it was not open to atmosphere at any time. It's like metal on metal scrapping....Souns like a brake lathe when turning a rotor only much louder....Maybe the A/C clutch coil is too weak to hold in when the pump is on max A/C???....It's not a belt squeal - I can say that for sure.....Can't exactly remember the pressures as my truck uses a different system than Freightliner and the pressures are less on the Ford....I think they were around 30 and 150 if I remember right.

Good point on the gap - there where shims in the clutch so I never paid any mind to it...What is the gap supposed to be. There's nothing in my Haynes book about A/C.

 

Read the caption of that diagram.