A/C questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

spdrcr29 · 03-27-2007, 08:29 AM

Does anyone know any sites that show schematics for a/c vacuum and controls?

I just redid my dash, and now the heater, fan, and the a/c work, but I can't seem to get the vents switched from the a/c vents to the defroster, and all the cables are attached. I did notice there is a vacuum selector attached to to the top lever on the a/c control, and someone apparently cut and plugged the line on the left as you look at the control. Is this my problem, and if so, where does the line connect?

sneakysnake · 03-27-2007, 08:45 AM

Heres some pics that might help to answer your Q's
http://67-72chevytrucks.com/vboard/s...d.php?t=225592

neonlarry · 03-27-2007, 03:23 PM

More than likely the flapper valve in the distribution box is broken. They can be fixed with some fabricated metal strips and/or some fiberglass (recommended) or but a new one ($$).

jhow66 · 03-27-2007, 03:47 PM

See if this helps:

spdrcr29 · 03-27-2007, 06:05 PM

Thanks for the help guys!
I got the inside/outside vent thing figured out at the vacuum switch, but the flapper must be broke, too, because it stays on the a/c vents. Oh well, it's a summer truck. I'll tear into the heater distribution assembly another day.

Any idea on how much dissassembly is required?

And, while we're on the a/c topic, what kind of money am I looking at to get it recharged. I know the o-rings/seals are good because it still has pressure, but it's not very cold anymore. A friend told me that if it was converted to 134 (?) it should be tagged. Since it doesn't denote being changed to the new refrigerant, he's assuming it's still got the r-12 in it. Suggestions?

spdrcr29 · 03-27-2007, 09:09 PM

After scouring the web and this forum, I'm thinking of Freeze 12 because it can supposedly be dropped in right over the R-12. It's either that or running it down to the local shop and having them do the Hotshot 414b, cuz my compressor is fine and I'm hearing the R-134 conversion is a pain......

Anybody had any luck with either the Freeze 12 or the Hotshot????

onetonk5 · 03-27-2007, 10:08 PM

my 134 conversion blows 37 out the vents in just about any weather...what more could you want?

sneakysnake · 03-28-2007, 09:03 AM

[QUOTE=Anybody had any luck with either the Freeze 12 or the Hotshot????[/QUOTE]

Ive used both, in auto and in refrigeration. Seems to work pretty well.They are a blend and have to be charged as a liquid so watch slugging the compressor.

03-27-2007, 08:29 AM	#1
spdrcr29 Registered User Join Date: Jan 2007 Location: Jackson, MI Posts: 78	A/C questions Does anyone know any sites that show schematics for a/c vacuum and controls? I just redid my dash, and now the heater, fan, and the a/c work, but I can't seem to get the vents switched from the a/c vents to the defroster, and all the cables are attached. I did notice there is a vacuum selector attached to to the top lever on the a/c control, and someone apparently cut and plugged the line on the left as you look at the control. Is this my problem, and if so, where does the line connect?

03-27-2007, 08:45 AM	#2
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Re: A/C questions Heres some pics that might help to answer your Q's http://67-72chevytrucks.com/vboard/s...d.php?t=225592

03-27-2007, 03:23 PM	#3
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,746	Re: A/C questions More than likely the flapper valve in the distribution box is broken. They can be fixed with some fabricated metal strips and/or some fiberglass (recommended) or but a new one ($$). __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

03-27-2007, 03:47 PM	#4
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: A/C questions See if this helps: Attached Images __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

03-27-2007, 06:05 PM	#5
spdrcr29 Registered User Join Date: Jan 2007 Location: Jackson, MI Posts: 78	Re: A/C questions Thanks for the help guys! I got the inside/outside vent thing figured out at the vacuum switch, but the flapper must be broke, too, because it stays on the a/c vents. Oh well, it's a summer truck. I'll tear into the heater distribution assembly another day. Any idea on how much dissassembly is required? And, while we're on the a/c topic, what kind of money am I looking at to get it recharged. I know the o-rings/seals are good because it still has pressure, but it's not very cold anymore. A friend told me that if it was converted to 134 (?) it should be tagged. Since it doesn't denote being changed to the new refrigerant, he's assuming it's still got the r-12 in it. Suggestions?

03-27-2007, 09:09 PM	#6
spdrcr29 Registered User Join Date: Jan 2007 Location: Jackson, MI Posts: 78	Re: A/C questions After scouring the web and this forum, I'm thinking of Freeze 12 because it can supposedly be dropped in right over the R-12. It's either that or running it down to the local shop and having them do the Hotshot 414b, cuz my compressor is fine and I'm hearing the R-134 conversion is a pain...... Anybody had any luck with either the Freeze 12 or the Hotshot????

03-27-2007, 10:08 PM	#7
onetonk5 Cereal Killer Join Date: Jan 2006 Location: Montgomery, Alabama Posts: 639	Re: A/C questions my 134 conversion blows 37 out the vents in just about any weather...what more could you want? __________________ If I dont do it....somebody else will.

03-28-2007, 09:03 AM	#8
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Re: A/C questions [QUOTE=Anybody had any luck with either the Freeze 12 or the Hotshot????[/QUOTE] Ive used both, in auto and in refrigeration. Seems to work pretty well.They are a blend and have to be charged as a liquid so watch slugging the compressor.



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