The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 08-19-2013, 12:28 PM   #1
SuperC10Tex
Registered User
 
SuperC10Tex's Avatar
 
Join Date: Oct 2012
Location: Texas
Posts: 567
Thumbs up R-12 to R-134a?

Need help; I have a dealer installed GM A/C unit (pic below). I have pulled the unit, I am going through it and lubing and cleaning it. I am about to reinstall.....I want to go from R-12 to R-134a. I see "retro-fit kits" for sale. My question is if I replace with new O-rings, Ester oil, service ports adaptors, and a new receiver/drier....I am good to go??? Also, the "service ports" are located where? Any help would be deeply appreciated!

__________________
1970 GMC Sierra Grande CST SWB Fleetside "Texas Touch"

"An intellectual is a man who takes more words than necessary to tell more than he knows"
SuperC10Tex is offline   Reply With Quote
Old 08-19-2013, 01:09 PM   #2
steelhorse
Senior Member
 
steelhorse's Avatar
 
Join Date: Apr 2008
Location: Franklinton NC
Posts: 1,309
Re: R-12 to R-134a?

It will work but if your condenser is the OE style it may not cool to well. If you replace your condenser with one made for R134 it will work much better.
steelhorse is offline   Reply With Quote
Old 08-19-2013, 02:06 PM   #3
Lattimer
Registered User
 
Lattimer's Avatar
 
Join Date: Jan 2013
Location: Mickleton, NJ
Posts: 1,776
Re: R-12 to R-134a?

I had an 80's Oldsmobile that I converted from R-12 to R-134. After the conversion the ac sucked really bad. It cooled, but it was about 50% as good as it was before that.

I had the conversion done by my father, he was an auto AC professional. I recall changing out the o-rings, putting in new oil, and changing a valve on the compressor.
__________________
Shawn

1970 Chevy C-10 SWB, 350, TKO 600 5 speed
My build http://67-72chevytrucks.com/vboard/s...d.php?t=559881
Lattimer is offline   Reply With Quote
Old 08-19-2013, 03:39 PM   #4
motorcritter
Registered User
 
motorcritter's Avatar
 
Join Date: Mar 2012
Location: Boulder, CO
Posts: 350
Re: R-12 to R-134a?

The later-style condensor will do quite a but to improve performance w/ R134a. I'd flush that evaporator out and pay close attention to pressures when recharging. The ports should be on your hoses/pipes. If not, have some built for it, custom fit.
Posted via Mobile Device
__________________
If 'that which does not kill me, makes me stronger', then I should be Superman by now!
motorcritter is offline   Reply With Quote
Old 08-19-2013, 04:14 PM   #5
MARKDTN
Registered User
 
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,165
Re: R-12 to R-134a?

Why are you changing? I'd stay R12
__________________
'83 K20-TPI
'73 C10
'79 C10-ex-diesel(SOLD)
'07 Tahoe(Son driving)
'14 Suburban-DD
'71 C10-current project
MARKDTN is offline   Reply With Quote
Old 08-19-2013, 04:15 PM   #6
tlcrz1972
Registered User
 
tlcrz1972's Avatar
 
Join Date: Apr 2013
Location: Gainesville, TEXAS
Posts: 658
Re: R-12 to R-134a?

Step one: Newer style condensor a must (no way around it)

Second step: get away from the POA style system, upgrade to a orfice/accumulator type setup.

Third step get rid of the big ole power robbing A6 compressor go to the short pancake type compressor or a sandin type.

If you do the first two and not the last it will only sort-of cool for you. I've tried it several ways with the A6 and once I finally changed to the small compressor it works great.
tlcrz1972 is offline   Reply With Quote
Old 08-19-2013, 04:23 PM   #7
SuperC10Tex
Registered User
 
SuperC10Tex's Avatar
 
Join Date: Oct 2012
Location: Texas
Posts: 567
Re: R-12 to R-134a?

Quote:
Originally Posted by MARKDTN View Post
Why are you changing? I'd stay R12
I have been looking at "Red Tek 12a", says it will go right into existing R-12 systems. If that is so, I will just change out old O-rings with new ones why I have it apart. anybody know about this "12a"??
__________________
1970 GMC Sierra Grande CST SWB Fleetside "Texas Touch"

"An intellectual is a man who takes more words than necessary to tell more than he knows"

Last edited by SuperC10Tex; 08-19-2013 at 04:34 PM.
SuperC10Tex is offline   Reply With Quote
Old 08-19-2013, 05:04 PM   #8
Bigdav160
Registered User
 
Bigdav160's Avatar
 
Join Date: Apr 2011
Location: Klein Texas
Posts: 3,852
Re: R-12 to R-134a?

Red Tek 12a is a hydrocarbon (from their MSDS)

From the boiling point I'd say it might be propane.
__________________
My Classics:
'72 K20 Suburban + '65 Dodge Town Wagon
'72 Corvette Roadster +'67 Corvette Roadster
'73 Z-28 Camaro
'63 Ford SWB Uni Pickup
'50 Ford Coupe
Bigdav160 is offline   Reply With Quote
Old 08-20-2013, 01:49 AM   #9
RichardJ
Registered User
 
Join Date: Apr 2010
Location: So Cal
Posts: 1,466
Re: R-12 to R-134a?

Quote:
Originally Posted by SuperC10Tex View Post
I would never take the time and effort for that underdash unit. One of the aftermarket units would be a much better solution. You'll have a lot more money in it, but it will be worth a lot more in every aspect.
__________________
'67 GMC 2500, 292, 4spd, AC
RichardJ is offline   Reply With Quote
Old 08-20-2013, 07:19 AM   #10
MARKDTN
Registered User
 
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,165
Re: R-12 to R-134a?

Quote:
Originally Posted by SuperC10Tex View Post
I have been looking at "Red Tek 12a", says it will go right into existing R-12 systems. If that is so, I will just change out old O-rings with new ones why I have it apart. anybody know about this "12a"??
Whatever you do either stay R12 or convert to R134. All the others are either 1) Hydrocarbons like Butane or Propane or 2) blends that have some giant molecules and some tiny ones. (Think ping-pong balls and BBs. When the BBs escape the system is not balanced and you have to blow the whole charge to balance it again)
__________________
'83 K20-TPI
'73 C10
'79 C10-ex-diesel(SOLD)
'07 Tahoe(Son driving)
'14 Suburban-DD
'71 C10-current project
MARKDTN is offline   Reply With Quote
Old 08-20-2013, 08:49 AM   #11
SuperC10Tex
Registered User
 
SuperC10Tex's Avatar
 
Join Date: Oct 2012
Location: Texas
Posts: 567
Re: R-12 to R-134a?

Quote:
Originally Posted by RichardJ View Post
I would never take the time and effort for that underdash unit. One of the aftermarket units would be a much better solution. You'll have a lot more money in it, but it will be worth a lot more in every aspect.
I see where you are coming from.....but this is a GM made unit, not a aftermarket one. It was installed by the dealership and looks to be a solid unit worth the effort!


Quote:
Originally Posted by MARKDTN View Post
Whatever you do either stay R12 or convert to R134. All the others are either 1) Hydrocarbons like Butane or Propane or 2) blends that have some giant molecules and some tiny ones. (Think ping-pong balls and BBs. When the BBs escape the system is not balanced and you have to blow the whole charge to balance it again)
I agree, after reading alot more....I am going to replace all old O-rings before I button it up. I have located a couple of cans of r12 for purchase, I will take it to a local shop and have them vacum/purge the sytem, check for leaks.....then I will have them Pro's install the r12. Thanks for the feedback Guys!!!

__________________
1970 GMC Sierra Grande CST SWB Fleetside "Texas Touch"

"An intellectual is a man who takes more words than necessary to tell more than he knows"
SuperC10Tex is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:22 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com