134a a/c conversion - The 1947 - Present Chevrolet & GMC Truck Message Board Network

68_c10_on20s · 07-15-2003, 04:20 PM

i have a factory a/c that hasnt worked in years lookin to get it fixed.my question is this does anyone make a conversion for these trucks as far as just all the right sized o-rings or what be nice to get a whole kit instead of chasing all the stuff down...?

70c10 · 07-15-2003, 05:08 PM

I know this is NOT the proper way to do this but I have bought the larger adapter ($3) to allow me to add the new freon and had no problems.

Mike C · 07-15-2003, 05:46 PM

Classic Industries has the adapters, Ester oil, and o-rings for about $30. I bought it last month along with a new drier and compressor but have not had a chance to do the conversion yet.

Gene · 07-15-2003, 06:44 PM

This is just my opinion but I wouldnt do it. I converted mine to 134a and it didnt get nearly as cold as the R12 did. I know they make an R12 replacement and have heard it works well but I would steer clear of changing over to the 134A.

project1971 · 07-15-2003, 07:49 PM

I do conversions all the time and have very little trouble with them. you do want to make sure you have enough air flow across the condensor since r 134 runs at higher head pressures. You just charge it with about 10% less. orings are the same across the board. any questions feel free to email me.

**old Rusty C10** · 07-15-2003, 08:01 PM

i remember hearing that you can do just what 70c10 did and its fine you dont have to change o rings etc just drain all the r 12 and stick in 134A

Hutch · 07-15-2003, 10:41 PM

Project71
I have the original a/c system that has been changed over to R134a.
I know that my system is working correctlyand is properly charged.
It will freeze you when the temperature is cool out but when it is really hot it lacks a lot.
How would you suggest to get more airflow across the condensor.
I have the standard factory setup with the fan/clutch and shroud.
Should I be running an electric fan setup?
I have heard that putting a larger condesor will help, is this a good idea?
An A/C technician stated that there is a valve that is designed to run the r12 systems that allows the compressor to cycle off too early and that this component should be changed to the newer style one designed for r134a when doing a conversion. It was something about letting the compressor run longer without cycling off.

Maybe I should use more insulation inside the cab and doors.
It would also be nice to find a blower fan that would move the air better than the original.

Thank you in advance

ddsmith · 07-16-2003, 12:32 AM

Hutch,
Even on a new install of an aftermarket A/C system they recommend a condenser fan. This can be wired to come on when the compressor cycles on and go off when the compressor is off. This should help maintain adequate heat transfer even when the vehicle isn't moving. They also strongly recommend maintaining the clutch driven original style engine fan and shroud. Just keep in mind that even properly operating systems have a temperature increase when the outside air temp increase or the vehicle is not in motion. Good luck and stay cool.

smokekiki · 07-16-2003, 08:24 AM

I converted my sub to 134.I added a fan to the condenser,it greatly improved the cooling.It keeps it cold on a hot day.And that is with all the heat that comes thru all those big windows.

a71CustomDeluxe · 07-16-2003, 05:55 PM

I would change all of the hoses. You need to flush the condenser and evaporator. The oil in the compressor needs to be changed to POE. I'd use blue (neoprene) o-rings. You will need a new receiver/drier. If the compressor pulley has been without a belt they sometimes have corrosion which chews up belts. With this setup you can charge with R134a but are still able to go back to R12 if you're unhappy with the R134a performance. For R134a you might also need to adjust the POA/STV. On my truck I use R12.

Richard

project1971 · 07-16-2003, 06:44 PM

Hutch
If you can get a larger condensor that would work also,more area and more fins per inch will help keep it cool. but if you run an electric fan wire it so it gets hot with the a/c is switched on so it runs even if the compressor has cycled off, the fan will last longer not kick off and on all the time. i have performed a conversion on a dodge where i got a newer style expansion valve for the r-134 even though the truck never had it so it is possible they have something similar for our trucks.

69sixpackbee · 07-16-2003, 07:42 PM

To optimize the cooling using 134 in R-12 systems, get a larger, condenser and add a fan as suggested. 134 needs approx. 20% MORE condenser area than that of R-12 even though you use approx. 20% LESS refrigerant. The old POA system works well when replacing the orifice with a Ford blue tube. It is HIGHLY recommended to change out your old A/C hoses with new barrier type EPDM pieces. It will work well just make sure that the orig. mixing doors seal properly and the heater valve is operating properly as well. You can add a manual shut-off throttling valve in the heater line as well.

07-15-2003, 04:20 PM	#1
68_c10_on20s Registered User Join Date: Aug 2002 Location: Waxahachie TX Posts: 773	134a a/c conversion i have a factory a/c that hasnt worked in years lookin to get it fixed.my question is this does anyone make a conversion for these trucks as far as just all the right sized o-rings or what be nice to get a whole kit instead of chasing all the stuff down...? __________________ 93 Fleet Budget Build http://s150.photobucket.com/albums/s...zted71/hoopty/

07-15-2003, 05:08 PM	#2
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,857	I know this is NOT the proper way to do this but I have bought the larger adapter ($3) to allow me to add the new freon and had no problems. __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

07-15-2003, 05:46 PM	#3
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,715	Classic Industries has the adapters, Ester oil, and o-rings for about $30. I bought it last month along with a new drier and compressor but have not had a chance to do the conversion yet. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

07-15-2003, 06:44 PM	#4
Gene Registered User Join Date: Aug 2002 Location: Muskogee, Oklahoma Posts: 2,914	This is just my opinion but I wouldnt do it. I converted mine to 134a and it didnt get nearly as cold as the R12 did. I know they make an R12 replacement and have heard it works well but I would steer clear of changing over to the 134A. __________________ 1971 SWB 4X4 Build BOARD MEMBER #5448 BOOMER SOONER!!!!

07-15-2003, 07:49 PM	#5
project1971 Registered User Join Date: Apr 2003 Location: Oklahoma City Posts: 605	I do conversions all the time and have very little trouble with them. you do want to make sure you have enough air flow across the condensor since r 134 runs at higher head pressures. You just charge it with about 10% less. orings are the same across the board. any questions feel free to email me. __________________ 2008 Ford FX2 Screw 1971 C10 project in shop now! 2004 Pontiac Grandam (wifes) 2000 Cavalier z24 (gas saver)

07-15-2003, 08:01 PM	#6
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,277	i remember hearing that you can do just what 70c10 did and its fine you dont have to change o rings etc just drain all the r 12 and stick in 134A __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

07-15-2003, 10:41 PM	#7
Hutch Registered User Join Date: Oct 2001 Location: Grapevine, Tx. Posts: 2,142	Project71 I have the original a/c system that has been changed over to R134a. I know that my system is working correctlyand is properly charged. It will freeze you when the temperature is cool out but when it is really hot it lacks a lot. How would you suggest to get more airflow across the condensor. I have the standard factory setup with the fan/clutch and shroud. Should I be running an electric fan setup? I have heard that putting a larger condesor will help, is this a good idea? An A/C technician stated that there is a valve that is designed to run the r12 systems that allows the compressor to cycle off too early and that this component should be changed to the newer style one designed for r134a when doing a conversion. It was something about letting the compressor run longer without cycling off. Maybe I should use more insulation inside the cab and doors. It would also be nice to find a blower fan that would move the air better than the original. Thank you in advance __________________ John Hutchison Grapevine,Texas 68 1/2 t swb 68 Mustang 69 Jaguar 71 1/2 t swb 88 Supra CompTs6m 93 Escort GT 2005 Corolla XRS

07-16-2003, 12:32 AM	#8
ddsmith Glowing since 1978 Join Date: Mar 2001 Location: Lusby,MD,USA Posts: 532	Hutch, Even on a new install of an aftermarket A/C system they recommend a condenser fan. This can be wired to come on when the compressor cycles on and go off when the compressor is off. This should help maintain adequate heat transfer even when the vehicle isn't moving. They also strongly recommend maintaining the clutch driven original style engine fan and shroud. Just keep in mind that even properly operating systems have a temperature increase when the outside air temp increase or the vehicle is not in motion. Good luck and stay cool. __________________ 66 Chevy C30 Stakebody Dump, PS,PB, 327cu in 71 Corvette Coupe 454 4 speed 69 Chevy C20 Custom Camper

07-16-2003, 08:24 AM	#9
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,474	I converted my sub to 134.I added a fan to the condenser,it greatly improved the cooling.It keeps it cold on a hot day.And that is with all the heat that comes thru all those big windows. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

07-16-2003, 05:55 PM	#10
a71CustomDeluxe Registered User Join Date: May 2003 Posts: 8	Re: 134a a/c conversion I would change all of the hoses. You need to flush the condenser and evaporator. The oil in the compressor needs to be changed to POE. I'd use blue (neoprene) o-rings. You will need a new receiver/drier. If the compressor pulley has been without a belt they sometimes have corrosion which chews up belts. With this setup you can charge with R134a but are still able to go back to R12 if you're unhappy with the R134a performance. For R134a you might also need to adjust the POA/STV. On my truck I use R12. Richard

07-16-2003, 06:44 PM	#11
project1971 Registered User Join Date: Apr 2003 Location: Oklahoma City Posts: 605	Hutch If you can get a larger condensor that would work also,more area and more fins per inch will help keep it cool. but if you run an electric fan wire it so it gets hot with the a/c is switched on so it runs even if the compressor has cycled off, the fan will last longer not kick off and on all the time. i have performed a conversion on a dodge where i got a newer style expansion valve for the r-134 even though the truck never had it so it is possible they have something similar for our trucks. __________________ 2008 Ford FX2 Screw 1971 C10 project in shop now! 2004 Pontiac Grandam (wifes) 2000 Cavalier z24 (gas saver)

07-16-2003, 07:42 PM	#12
69sixpackbee Registered User Join Date: Jan 2001 Location: Sabinal, Texas Posts: 1,706	To optimize the cooling using 134 in R-12 systems, get a larger, condenser and add a fan as suggested. 134 needs approx. 20% MORE condenser area than that of R-12 even though you use approx. 20% LESS refrigerant. The old POA system works well when replacing the orifice with a Ford blue tube. It is HIGHLY recommended to change out your old A/C hoses with new barrier type EPDM pieces. It will work well just make sure that the orig. mixing doors seal properly and the heater valve is operating properly as well. You can add a manual shut-off throttling valve in the heater line as well.



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