Help with A/C recharge 92 explorer

[xitsmike]

92 explorer EB
just put in a new a/c compressor since mine had been fried, put in one from a junkyard. i bled the old 134a (or R12?) without any pump. the install went smooth. Im not sure wat refrigerant was in it, i believe r12 because thats what it says on the blower and as far as i can tell it doesnt look like anything was converted. On my old compressor there are no stickers or writing indicating what gas is used but on the one i got from the junkyard from the same truck and year has a sticker on it says to only use 134a. so anway, i got a retrofit kit with 3 cans of 134a. i put the adapters on, started the truck and put ac on max, started filling it from the 1st can. i had the hose hooked up fine and it seemed to fill very slowly. After 10 min the can was not empty but the pressure gauge had gone up to 45 psi, the compessor had not clicked on at all during this 1st can. The ac did not seem cold inside. So i pierce another can and hook it up. at first the gauge reads ~20 psi (it had just read 45 when first can was taken off) and then starts to fill Very quickly, shootin to 45 in about 5 seconds and then the compressor clicked on for 3 seconds and gauge went down to 0, compressor would shut off and it would go back up to 45 and continue to do this. Now i dont know if it should be doing this or not but either way it wasnt for the first can so that tells me something is wrong. I dont know much but my guess is that the compressor is compressing the gas from the low end to the high end every time it clicks on while filling and this is dropping the gauge back down to 0, The only thing that doesnt make sense to me then is why it didnt do this at all for the first can, each can is 15 oz and the spec on the truck says 1.75 lb to fill.

OK all that said, am i forgetting anything or doing anything wrong, is the compressor suppose to click on and off as it fills to send the gas to the high end, and am i suppose to put a different ammount of the 134a then the r12 and if so whats 1.75 lb of r12 convert to in 134a. Does it sound like the junkyard compressor may be broke? Maybe these kits are just junk and i should go get it filled professionally? I appreciate any help.

thanks, mike

 

[Glacier991]

Go to the useful threads forum and there is a thread on converting to 134a... in actuality the thread title ought to be changed because it turned into a general AC thread. And sadly, you didn't do very much right by just swapping out the compressor. Go read that thread and then ask any Q's you have left over. You have a lot of work ahead of you.

 

[mctoy]

Mike,
Very first thing that I see is that you dont say that you have evacuated the system (Vacuum) B4 installing refrigerant....(?) If there is air in the system, you will have high headpressure, poor/no cooling, not able to get proper amt. of refrigerant in etc. You REALLY need to have the system put into a vacuum. Cant over emphasize it enough! With air in the system, you also have moisture...No.1 enemy of your compressor! Also dont know if your system is clean...When the old comp. burnt out, it likely deposited a whole bunch of gunk into the lines. YOU MUST HAVE A CLEAN - DRY, SYSTEM to start with! You need to know what type refrigerant you require. Just because you have (Or dont have?) an R34 comp, doesnt mean you can just put it in there. The system must match. Lots of variables. Orifice/metering device size being one. You must have the correct oil in the compressor as well. Take it to a gas station, or trusted shop,....shouldnt be more than 40 or so if you supply refrigerant. Not tryin to 'bust yer chops', but there is alot more to it than driving to Walmart for a (So called IMHO) kit.

 

[xitsmike]

ok, thanks for the info. I did imply that i didnt get it vacuumed when i said i bled it without a pump. I was told converting between the 2 refrigerants was just a matter of the fittings and that the new 134a gas was fully compliable with all r12 parts, the gas also has the oil pre added to it. The shop i called about this gave me a quote of 60/lb for refrigerant + couple hours to convert and fill, seemed like a BIG ripoff to me. i got the nearly 3lbs + hose and adapter kit for 40 at an aid auto store. But i guess ill call around a few places then.

But my main question still remains, when filling the system from the low sid nozzle should the compressor click on and off to compress it to the high side and as it does so the gauge would go up n down?

thanks,
mike

 

[Eneurb]

Did you change your oriface tube and accumulator and flush the system after replacing you compressor?? If not, you may have a restriction.

 

[xitsmike]

no i did not

 

[Glacier991]

A "crumped" (eg. failed) compressor requires that the system be taken apart, and everything flushed until clean, or replaced, a new orifice tube be installed, a new accumulator installed. Good practice also adds an inline filter on the return line to the compressor.

The system will have appropriate oil for the type of refrigerant being used added to it as per manufacturers spec. It will then need to be evacuated for about 30-45 minutes to remove air and moisure. THEN you can add your refrigerant. If you haven't please go read the thread I mentioned.

(and while that thread answers your question, to save you time, the answer is yes, the low side should fall with the compressor on, and when it clicks off the low side will rise.)

 

[xitsmike]

ok thanks for all the info, yea i shoulda looked on the forums before i went to the store and saw this kit and was told it works fine. And i did read that thread u mentioned and a few others, lots of info i wish i had before i bought this. I even asked the guy 'is this thing for real or is it just a waste of money honestly' and he said it works lol so much for that 40 bucks.

in your guys experience with shops a) where should i go for best price while having it done right, ford dealership, gas station mechanic, a/c & radiator shop? and b) what should i expect as far as cost.

lastly, i do own an air compressor just not a vacuum pump, how hard would it be for me and what additional tools would i need if i wanted to still try this myself.

thanks,
mike