A/C Conversion R12 to R134
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Postmaster
Joined: Mar 2008
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From: Prairieville, La
A/C Conversion R12 to R134
I have converted my 1983 f-150 to 134 refrigerant. It does not blow as cold as the r12. Is it possible to put a higher rpm motor for the fan to circulate the air in the cab better?
Logistics Pro
Joined: Jan 2007
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From: Martinsburg, WV
How did you convert it? did you change the orifice tube from blue to red or orange depending on cab size, did you change the cutoff pressure at the cycle switch? And please tell me you flushed the system and changed the accumulator. Did you start at 80% of refrigerant and oil charge and work up to acceptable pressures. I have done several retrofits on older fords and gm's All of them you can hang sides of beef in. If properly done, a retrofit can run just as cold or even colder than r12.
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Postmaster
Joined: Mar 2008
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From: Prairieville, La
Actually I did change the orifice tube. I believe it was blue and I put a blue one back in. I pulled a vacuum on the system after pouring rubbing alcohol thru the system and replacing the accumulator. I am not sure what the cutoff pressure at the cycle switch is.I did put another plug switch on the accumulator,is that what you are talking about? The system blows cold, but I am afraid that it will not keep up when the hot summer days come around. I also wondered if tinting my windows would help to make a difference.
Oh, I also switched all of the o-rings out with new green o-rings.
Oh, I also switched all of the o-rings out with new green o-rings.
Logistics Pro
Joined: Jan 2007
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From: Martinsburg, WV
Ok, good, you did better than most do. On the orifice tube, you would want a red tube for a standard cab, and an orange tube for an extended cab/crew cab. If you live in an extremely hot area, I would recommend the VOV, variable orifice valve, it automatically adjusts according to the needs placed on the system, but is not really needed unless your in a more extreme climate. To adjust the cutoff pressure you use the small straight slot screw between the contacts on the switch., the one on the accumulator.
Here is some info on the tubes, color, orifice size tolerance and Four Seasons part #.
Blue - .0655-.0685 - FS Part # 38621
Red - .0605-.0655 - FS Part # 38635
Orange - .056-.059 - FS Part # 38639
VOV - for under 105 degree averages - FS Part # 38902
VOV - for over 105 degree averages - FS Part # 38904
To set the switch and refrigerant charge to the proper pressures you need a proper gauge set and be using the theoretical temp part on the guage and get it to just above freezing. 0 deg C on the low side, should be the green line and numbers on the low side gauge.
Here is some info on the tubes, color, orifice size tolerance and Four Seasons part #.
Blue - .0655-.0685 - FS Part # 38621
Red - .0605-.0655 - FS Part # 38635
Orange - .056-.059 - FS Part # 38639
VOV - for under 105 degree averages - FS Part # 38902
VOV - for over 105 degree averages - FS Part # 38904
To set the switch and refrigerant charge to the proper pressures you need a proper gauge set and be using the theoretical temp part on the guage and get it to just above freezing. 0 deg C on the low side, should be the green line and numbers on the low side gauge.
Methanoholic
Joined: Mar 2009
Posts: 6,442
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From: Maine (NorCal Native)
Archion,
Are the Gauges the same for R134 as R12, I have a set of R12 gauges I bought new back in the 80's...
It's my belief they are incompatible.
I've done a pile of R12 systems, have never touched a 134 system.
Used to know and understand AC systems...
Been a long time though, don't use it, lose it syndrome has set in along with my age!
Sorry for butting in!
-Enjoy
fh : )_~
Are the Gauges the same for R134 as R12, I have a set of R12 gauges I bought new back in the 80's...
It's my belief they are incompatible.
I've done a pile of R12 systems, have never touched a 134 system.
Used to know and understand AC systems...
Been a long time though, don't use it, lose it syndrome has set in along with my age!
Sorry for butting in!
-Enjoy
fh : )_~
Logistics Pro
Joined: Jan 2007
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From: Martinsburg, WV
Different gauges yes, but you can get combo gauges now, that's what I have now since my other ones busted last time I moved. It has couplers to adapt over to 134 when needed. If you know R-12/R-22 then you know R-134, just different pressures, the principals remain the same.
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Posting Guru
Joined: Nov 2007
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From: West Texas
Something often overlooked is your fan clutch. Make sure it's really pulling some air when the truck is warmed up and it's hot out. Normally you would hear it roar at least a little bit inside when it engages. If it's old it's probably a good idea to replace it anyway since you just converted the system. It will help the condenser do it's job much better.
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Thread Starter
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Postmaster
Joined: Mar 2008
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From: Prairieville, La
Archion, thanks for the info and part numbers on the orifice tubes. I think i will try the vov under 105 unit. I know I will have to evac the system again. Is there anything else i need to do before recharging the system? If I have time I am going to try it this weekend.
RRranch, I replaced my fan clutch when I refreshed the engine. Thanks for everyone's help.
RRranch, I replaced my fan clutch when I refreshed the engine. Thanks for everyone's help.
Logistics Pro
Joined: Jan 2007
Posts: 3,829
Likes: 104
From: Martinsburg, WV
Not really, just make sure the system is clean and sealed up good. As RRranch said, make sure your fan clutch is functioning properly and that your fan shroud is still intact, also make sure there is no clogging in the condenser or rad fins.
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
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From: Exmore, VA
We did my truck several years ago and the only issue I have with it is the combination of underhood heat from the 460 and Ford's deletion of the water shut off valve for the heater core. On hot days after a restart, it takes a bit to get real cold again, but you can hang a side of beef in there.
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Postmaster
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From: Prairieville, La
I wanted to say thanks to Archion. I went with the VOV under 105 degree orifice tube.I had the blue orifice tube in upside down also and only had a pound and a half of 134 in my system.
My friend works at a dealership and they have a nice machine for doing a vacuum and recharge. I now have the tube in correctly, 3lbs of 134, and am blowing cold a/c at 48 degrees on low max.
I think my next move is to tint my windows to help keep the heat out. My friend also told me to put in a shutoff on the heater core line to keep the hot water from entering the cab.
My friend works at a dealership and they have a nice machine for doing a vacuum and recharge. I now have the tube in correctly, 3lbs of 134, and am blowing cold a/c at 48 degrees on low max.
I think my next move is to tint my windows to help keep the heat out. My friend also told me to put in a shutoff on the heater core line to keep the hot water from entering the cab.
Posting Guru
Joined: Jan 2005
Posts: 1,299
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From: The Vieux Ford, Kansas
Did it not come with a shut off? My 82 and my 79 had a little vacuum coolant valve that shuts the flow off automatically when the AC lever in the cab is switched on. If you don't have on it will help the AC in my 79 doesn't work but putting the selector in the AC position and closing that valve does cool thing down a pit especially for the passenger.
-Johnboy
-Johnboy
Logistics Pro
Joined: Jan 2007
Posts: 3,829
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From: Martinsburg, WV
No problem at all, glad that worked out for you, on the universal heater valves, here are the Four season #s
84705 - 1/2"
84706 - 5/8"
84707 - 3/4"
84708 - 1"
These are the manual type, like a spigot.
84705 - 1/2"
84706 - 5/8"
84707 - 3/4"
84708 - 1"
These are the manual type, like a spigot.
Thread Starter
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Postmaster
Joined: Mar 2008
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From: Prairieville, La
Update
Archion had mentioned in here to check and clean the a/c motor. I want to re advise this. It could save you a lot of headache. I had about a pound of leaves around my condenser.
If you remove the 4 screws and unplug the harness, it is easy access to clean your condenser. Once the debris is cleared, spray the condenser with brake cleaner, then rinse the condenser with a garden hose, and blow dry with compressed air. Also turn your air to heat while the motor is out and this will give easy access to clean out between your fender and cab.
My dad and I did this today and my air blows 4 degrees colder than it did before cleaning. I had to keep it on high the entire time to stay cool before. Now I can not go higher than medium. It was 90 degrees outside today and the air was blowing at 44 degrees on low max compared to 48 three weeks ago.
If you remove the 4 screws and unplug the harness, it is easy access to clean your condenser. Once the debris is cleared, spray the condenser with brake cleaner, then rinse the condenser with a garden hose, and blow dry with compressed air. Also turn your air to heat while the motor is out and this will give easy access to clean out between your fender and cab.
My dad and I did this today and my air blows 4 degrees colder than it did before cleaning. I had to keep it on high the entire time to stay cool before. Now I can not go higher than medium. It was 90 degrees outside today and the air was blowing at 44 degrees on low max compared to 48 three weeks ago.