A/C how much is full.
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Senior User
Joined: May 2001
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From: Columbia, TN
A/C how much is full.
How many onces does it take to fill recharge the ac in an older truck? I have a 75 f100 with a 390 in it and it has an aftermarket AC in it, I think.
Thanks David
Thanks David
Thread Starter
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Senior User
Joined: May 2001
Posts: 178
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From: Columbia, TN
A/C how much is full.
I got one last night, how much do I put in. Its an R12 system with R134 in it. I have an R12 gauge can I go by the instruction for it since I have r134?
Any help
Any help
New User
Joined: Aug 2001
Posts: 9
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A/C how much is full.
depends on the system.
back when I could buy R12, I would pull a 28" vacumm on the system for an hour or so then add one can of ac oil, then
hook up the gauges and add one can of R12 then start the engine
and turn on the ac. then add R12 to the low side until the low side hit 30 psi or the high side hit 180 psi ( and stayed there).
It usually took 3-4 one pound cans from empty.
On cars with the sight glass , you can get by without gauges,
just add R12 until the bubbles go away . ( after vaccumming the system down! if you fail to vaccumm the system down the bubbles will not go away, and you'll ad R12 'till the pump liquid locks. Liquid freon doesn't compress at all, liquid lock leads to sheared input shaft keys, multi piece input shafts, multi piece con rods on piston pumps, cracked pump housings...... )
back when I could buy R12, I would pull a 28" vacumm on the system for an hour or so then add one can of ac oil, then
hook up the gauges and add one can of R12 then start the engine
and turn on the ac. then add R12 to the low side until the low side hit 30 psi or the high side hit 180 psi ( and stayed there).
It usually took 3-4 one pound cans from empty.
On cars with the sight glass , you can get by without gauges,
just add R12 until the bubbles go away . ( after vaccumming the system down! if you fail to vaccumm the system down the bubbles will not go away, and you'll ad R12 'till the pump liquid locks. Liquid freon doesn't compress at all, liquid lock leads to sheared input shaft keys, multi piece input shafts, multi piece con rods on piston pumps, cracked pump housings...... )
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Joined: Jul 2001
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From: Gainesville, FL
A/C how much is full.
Blue,
When filling an R12 system with R134a you must insure that the correct oil is used. That means the R12 oil must be blown out of the condenser,evaporator,lines and compressor. Then add the R134a oil. Then pull a vacuum on the system. Close off the system and see if it will hold a vacuum for an hour or so. if so, then you can add your R134a. The expansion valve can be replaced to help efficiency loss from the conversion or you can live with the one you got. The dryer at the condenser should have a sight glass on in it and it will help you determine your refridgerant needed. 2.2lbs is a common amount that's about 35.2 ounces. Watch your sight glass for bubbles, that's the best way.
Good Luck, HaveFun, Kingfisher
When filling an R12 system with R134a you must insure that the correct oil is used. That means the R12 oil must be blown out of the condenser,evaporator,lines and compressor. Then add the R134a oil. Then pull a vacuum on the system. Close off the system and see if it will hold a vacuum for an hour or so. if so, then you can add your R134a. The expansion valve can be replaced to help efficiency loss from the conversion or you can live with the one you got. The dryer at the condenser should have a sight glass on in it and it will help you determine your refridgerant needed. 2.2lbs is a common amount that's about 35.2 ounces. Watch your sight glass for bubbles, that's the best way.
Good Luck, HaveFun, Kingfisher
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From: MT
A/C how much is full.
Instead of messing with changing the oil in the system to convert to 134a just use a freon call Hot Shot, I think it is r416..I would have to double check..I use it all the time as a direct replacement for r-12 in walkin coolers and freezers..Have also used it in cars..The pressures are about the same as 12 and it works better then 134a..No need to change the oil..Just charge until the sight glass shows no bubbles..