I just purchased an 87 f150 xlt lariat and the ac is not cold. I know this model would have orginally had R12 but how can I tell if the previous owner converted to R134? Also, the plate on the outside of the compressor seems to be sticking (spins and stops), does that mean the clutch is gone or is it the whole compressor that needs to be replaced? It looks like a refurbed compressior to begin with. Thanks for any help!!

 

small fittings = r12

large fittings = r134

look at a 94 or later vehicle and that is r134 fitting size

 

spinning and stopping means it is probably just out of R134a(if it has been converted) or R12. I have an 88 and i believe it was converted. It blows nice and cold. I know you can buy conversion kits. I wouldnt touch the compresser until you recharge your a/c. I would just get a retrofit kit and see what happens. ALot of people say you need to change out all the o rings because the oil in the two (r12 & r134a) are not compatible. I dont know what it will do if you do not do this, or if it was done on mine when it was converted. I bought a retrofit kit (not to retrofit, but got it because it came with everything i wanted) and it didnt say anything about changing o rings. so i cant really say for sure.

Also, welcome to FTE!

 

I retroed my 93 about 5 years ago. I flushed it and that was it.Didn't change anything else and it has worked fine.

 

Do you have a rough cost estimate for the retrofit? I am not a mechanic nor do I have extensive knowledge of cars, is it something anyone can do? I assume so if the sell a kit.

I have learned quite a bit just going through the threads the last week or so. This is a very cool site, thanks for the welcome and great information!!!

 

If its been converted to R134a, there should be a quick release fitting screwed on to the Hi and Lo pressure ports. Also you're supposed to place a sticker in the area indicating the system has been converted to R134a.

From your description, the clutch is short cycling which normally indicates a low refrigerant charge. You need to find and fix the leak before you go any further.

 

i recommend taking it to an air conditioning shop.

 

Retro-fits are available at most auto parts stores. I think they run from about $30 to $50. They come with the refrigerant, oil, and maybe a charging hose. I had to change the compressor on my '93 about 3 years ago. I switched over to R134A at that time and it has been working great ever since. It would be best to change the orifice tube (about $2) and the accumulator (about $25) while you are at it.

 

Also don't forget that you don't have to convert it over. There are products that you can add to an R12 system to fill it up. One I know of is called Freeze 12.

Connectors are the best indication of if it's been changed. If you're not sure, take it to a shop. They'll know right away, and if it's just a little low they will probably just charge it with whatever is in there for a small fee.

 

What are your thoughts on taking it to the shop for a diagnosis and based on what they find (leak, low freon, etc), do the work myself? I'm not sure what the AC shops charge to look at it but maybe that's a good idea???

 

Before you work on it, you'll have to have them at least discharge the system. Especially if it's R12.

Other then that it's pretty simple to work on the A/C system. I've done it a few times on various cars.

Once you're done, have them vacuum the system out (gets rid of moisture). This will also tell them if there are any leaks as it should hold vacuum. Then have them refill it. You can do it by yourself, but R134 is by weight and it's nice to let the computer figure it out. R12 was nice because you can get away with overcharging the system, so all you needed was the gauges.

Also A/C systems loose a small amount every year, so even thought everything is fine they will need to be topped off. If that's the case, just let them do it.

 

spray a soap solution around fittings and on condenser if any bubbles there is a leak.

 

As mentioned many times above, buy a retrofit kit. or take your calipers and measure the fittings, then go to your local parts store, act like you know what you're doing and open the retrofit kit box and measure the known r-134a fittings. as far as the clutch goes, i am not an expert(but i did just put one on my truck last weekend), but if the armature is not turning, the compressor is not turning. that armature has a female spline that mates to the male spline on the compressor. check voltage on your clutch connection,toggling the switch in the cab to see if it is getting the voltage necessary to create the magnetic force needed to mate the armature and rotor/pulley. also if your clutch has worn considerably, the gap between the armature and rotor/pulley may have become too wide for that magnetic reaction to take place. armature-to-rotor/pulley air gap should be set between .018-.030 inches, measured in at least three equi-distant points. Good Luck

 

oops-sorry. somehow i missed your reply stating that you were somewhat of a novice in terms of wrech-turning. If you or someone you trust has a decent understanding of mechanical knowledge(not auto-mechanics, but cause/effect-square peg/round hole) you can do most r-134 work yourself with a haynes manual. if you still think its over your head, beware that a/c shops love when you bring them "torn into" systems. the bill will almost automatically double.

 

Thanks for "dumming it down" for me gtro8098!!! When I went home and tried pulling the low pressure cap (blue), it made a hissing sound like I was opening a valve. Is that normal? I didn't take it all the way off incase something was wrong or broken causing the freon to leak. I had a chance to look under the hood of a buddy's 97 f150 and saw his cap was gray. When he pulled his off there was no hissing sound. Just curious? I want to get the cap off so I can compare fittings.