next question. will thr a c compressor of my 91 f-350 with a 460 fit on my 90 f-250 with a 351 in it. i took measurements and the compressor seems to be the same. all of the hoses and lines look the same.the comp on my 91 was converted to r 134 awhile ago and works fine.the 90 is stillr 12 and hasent worked since the purchase of that truck. so i guess the next question is will the parts on the 460 work on the 351 ? my 91 isint road worthy anymore. has anyone ever swapped these parts? thanks FFF

 

There shouldn't be any difference between most of those components. I usually cross reference a few online parts houses to make sure. Before swapping things over what is wrong with the 90 w/R-12? I am not a fan of the R-12 to R-134a conversion. I prefer drop-in replacements or good ol' R-12. No sense going through this chinese fire drill only end up with the same issue or worse Black Death

 

thanks for the reply rla 2005, not sure whats wrong with the ac compressor cant get it to kick in, ive pulled the switch off and jumped it with a wire.still no go. i just thought it would be easier to switch things over .is there something else i should try to do? the local napa sells a replacement for r12 called freeze 12,need to get it working so any help would be great thanks FFF

 

Where was the switch you pulled off?
Freeze 12 is good, that is what I use.

 

I jumped the switch on the cansiter, not sure of proper name. got the compressor to click on now but its blowing warm air. any ideas?

 

That would be the clutch cycle switch. It also functions as a low pressure cutoff. If the refrigerant pressure is too low it keeps the compressor from kicking on. You are low on R-12, that's why it won't turn on without jumpering that switch.

The right thing to do now is to evacuate the system, pump it down, look for and repair any leaks. If the refrigerant is very low or completely gone it would be a wise idea to replace the receiver/drier. It has a desiccant in it to abosrb moisture. It may be contaminated at this point. If you open up the system you might as well spring for a new orifice tube. They usually run less than $5 USD. Inspecting the orifice tube gives a quick indication if the system has any debris in it. A small amount is normal. If it is anywhere close to the pics in the link I sent earlier you have a much larger problem.

Once the leaks have been repaired and new R/D installed it's time to pump it down again, check one more time to see if it holds a vacuum, then charge it by weight with refrigerant of choice.

 

thanks rla 2005, im gonna dive into this a little deeper tommorow when ive got time.thanks again for the info..FFF