I have a 93 f150 that has been bullet proof for the past 178000 miles, however the AC went out last summer and I need to get it fixed befoer it gets hot down here. I've priced out a compressor and clutch and was going to swap them out this weekend. I'll be converting it over to 134 since r 12 is the price of gold.
What else do I need to do? What all needs to be replaced??

Thanks!

 

I recommend that you proceed cautiously - search these forums & read carefully. I am an amateur and have had success with a R-12 system and in converting a R-12 system to R-134a. On the other hand there are a LOT of pitfalls.

First you need to really understand the whole system, at least at a general level. For example, it would be OK for a mechanic to replace the clutch if it was bad, because the clutch is relatively independent. If, on the other hand, the compressor has failed mechanically, this means metal particles being distributed through the system. Put in a new compressor and the junk from the old compressor will eat the new one.

If the problem is related to losing refrigerant, then you need to find and fix ALL the leaks, not just some of them. This is "do-able", but you have do do it, or you will do a lot of work AND spend a lot of $$$ for nothing.

Old advice is that replacing R-12 with R-134a would be a loser. I did a GMC S-15 and it worked great. I did replace the compressor seal, but I did not find all the leaks, so a year later I will have to add some refrigerant. I am OK with this.

I can say more, but I'll pause to let others participate and to let you ask questions.

Final question: How do you know you need a new compressor?

 

I would find out "what went out" to determine the extent of the repair vs changing everything. Does the clutch engage,, rapid cycle. What are the high side low side pressures. I would do a diagnostis before deciding to convert. I might convert but I would not convert until I understood the problem. One small point all o-rings have to be changed out for the conversion and there is about a 10% loss in efficiency on 134. Just my $.01 worth. If you get the data I will help you sort though what needs to be done, With no data,, I would not guess the problem. Jim

 

My compressor is not cooling. It makes a clicking noise when turned on. It also seems to put a strain on my engine when on. Meaning it pulls the motor down.
Last summer I had a guy put r12 in it. The pressure was good. It cooled when rpm's were increased, but not when at idle. After running it a little the clicking increased and sounds awfull when running. It still does not cool. I assume that is the compressor that needs to be replaced. While I do not have the equip to recharge it, I planned on doing the hard part, replacing the compressor and associated parts and take it in to have it charged. However I do not know all the parts to do. O-rings, dryer, compressor w/ clutch assembly what else????

 

Just as an example of what can happen: An overcharge will result in liquid refrigerant going through the compressor. This is called "slugging" and it does sound awful. I have had a pro do this to me once and my compressor survived it. I guess he wanted a little more profit for selling more refrigerant. From then on I did my own work.

You can take a "shot-gun" approach and replace the compressor and everything that could be contaminated. This varys from system to system. Some systems have filters, so anything down-stream of the filter should be clean. The filter often "hides" in another component (e.g.: receiver/drier/filter), so you really need documentation of your exact system. A good parts guy will have the pictures to help you with this, but notice I said "good". There are a lot of not-so-good parts guys who will just sell you anything they can.

 

You say the AC "went out". What happened? You mention replacing the compressor so I will assume the worst, an internal compressor failure.
Over time it's been concluded that when a compressor has a catastrophic failure, a "firewall foreward" replacement is the best course. This is due to debris, cooked oil and acids hiding in the old parts, flushing often doesn;t get it all out. A little judicious "used part shopping" can find the condenser and lines from a truck with an intact system. The evaporator should be flushed (lacquer thinner and lots of compressed air is cheap) along with any lines that don't contain an orifice or muffler. The accumulator and orifice MUST be replaced. Not doing these things can damage an expensive compressor. Obviously, replace all of the O-rings in the fittings.
The old accumulator is not compatible with R-134 and at 14 years the dessiccant bag is likely saturated and can fail, killing the compressor. It is also the main filter for the system, equate it to your oil filter.
(opinion on) Stay away from inexpensive reman compressors like Everco or Four Seasons. They have a high failure rate and quality is a crap shoot. BTDT. There are new compressors available and also some quality remans. You will pay more for quality, but using a cheap compressor can cost way more in the long run.(opinion off).
When converting to R-134, Ester based oil used to be recommended. There are newer PAG oils available now that are better for retrofits. "Double end capped" PAG oil is now preferred.
When doing a conversion, don't use the kit offered in most parts stores. These are known in the trade as "Death Kits". They usually contain Ester oil, sealers and shady performance "boosters". The gauge included is all but useless for determining proper system pressures. The only good thing in the kits is the can tap, they actually work pretty good. You can get the tap separately.
Put together your own "kit". Get steel conversion fittings form NAPA, the aluminum ones often leak. Use only virgin R-134a with no sealers or additives. UV dye in the refrigerant is ok. Buy enough to get at least 85% of the original R-12 amount. Get enough oil for the recommended capacity.
You can rent a manifold gauge set and vacuum pump from many parts stores.
One often overlooked part that is essential to AC operation is the fan clutch. They get weak over the years. The engine is forgiving of a weak fan clutch, but the AC is not. Especially if using R-134a. The weak clutch can't move near enough air at low speeds to cool the condenser. This is one of the main reasons R134a conversions "don't work well". If it's more than 4 years old, replace it. Motorcraft is the best bet for the fan clutch.Aftermarket replacements often don't move quite enough air for good AC operation at idle. That's your judgement call.
I've done many repairs and conversions on these trucks. When done as I've described here, you can't tell much difference from R-12. If you do it right, you'll only do it once in the remaining life of the truck.
Good luck.