A/C & heater control vacuum line info

Status
Not open for further replies.

Gonzo1970

G-Body Guru
Sep 30, 2018
898
1,302
93
One of our fellow members (UNGN) suggested using a small nut and bolt thru where the selector lever is attached. Apparently it tightens up the connection which helps eliminate, or decreases vacuum loss.
I thought that was a useful tip.

Yeah, I saw that.. But if Im going to get my fingers in there, I'd rather just replace it and be done with it. Napa has them for $25

-Gonz
 
  • Like
Reactions: 1 user

MrSony

Geezer
Nov 15, 2014
6,791
6,675
113
Des Moines, Iowa
You will hear a leak as well when you switch it from on to off, be aware of that. Just the system "powering down".
 
  • Like
Reactions: 1 user

Longroof79

Rocket Powered Basset Hound
G-Body of the Month
Oct 14, 2008
12,156
9,762
113
Gainesville, Fl
Yeah, I saw that.. But if Im going to get my fingers in there, I'd rather just replace it and be done with it. Napa has them for $25

-Gonz
Before I realized you can buy them over the counter, I scavenged thru some old control units until I found one that worked satisfactorily. The next time I will try the small nut and bolt trick,,,or self tapping screw. Awhile back when I was looking for a replacement, the ones I've seen for sale, they wanted around $50.00 for that little piece of crap.
 

Gonzo1970

G-Body Guru
Sep 30, 2018
898
1,302
93
You will hear a leak as well when you switch it from on to off, be aware of that. Just the system "powering down".

Yep! Knew that.. currently, it just continually leaks.

Before I realized you can buy them over the counter, I scavenged thru some old control units until I found one that worked satisfactorily. The next time I will try the small nut and bolt trick,,,or self tapping screw. Awhile back when I was looking for a replacement, the ones I've seen for sale, they wanted around $50.00 for that little piece of crap.

They still are. Advance Auto an Napa are the only two with them for $25. Even Rockauto is still $50 :blam:

-Gonz
 
  • Like
Reactions: 1 user

uneek1976

G-Body Guru
Jul 24, 2009
653
129
43
Sugar Grove IL/ Chicago
I have a question, I just noticed that mine is only blowing at the bottom and not through the vents. And after reading this thread I only have one vacuum ball which is on the driver side under the battery with nothing hooked to it and I may have removed the other vacuum ball when doing my swap if it was one I can't remember. Now I do have vacuum lines coming from under the dash that one goes to the heater control valve and the other going to my intake. How do I get the vents to blow?
 

MrSony

Geezer
Nov 15, 2014
6,791
6,675
113
Des Moines, Iowa
Can the mods make a sticky thread about this please?. There is a white/grey line that goes to the valve in one of the heater core lines. Specifically the one that lets coolant IN to the core. The dark purple/pink line goes from the hvac controls in the dash to a small port on a 2 port vacuum tank/reservoir/ball/canister. Larger port goes to a manifold vacuum source with a check valve inbetween. Ball typically hangs on the bracket on the ac box near the passenger valve cover. Pic of Hafrod's engine for ball location.
idk anything about LS engines, but you need to be connected to manifold vacuum.
20170609_185028_resized.jpg
 
  • Like
Reactions: 1 users

uneek1976

G-Body Guru
Jul 24, 2009
653
129
43
Sugar Grove IL/ Chicago
Thanks for that pic. I don't have that vacuum ball but I do have one in the fender area on the driver side under the battery tray. I wonder if I can get away with using that one or if I have to go a find one that goes there like in the pic.
 

MrSony

Geezer
Nov 15, 2014
6,791
6,675
113
Des Moines, Iowa
Thanks for that pic. I don't have that vacuum ball but I do have one in the fender area on the driver side under the battery tray. I wonder if I can get away with using that one or if I have to go a find one that goes there like in the pic.
Some g bodies (olds powered ones as far as I know are the only ones that did so) had it on the inner fender or under the battery tray as you described. If it only has 1 port, it's for cruise control.
 
  • Like
Reactions: 1 user

uneek1976

G-Body Guru
Jul 24, 2009
653
129
43
Sugar Grove IL/ Chicago
You are correct, that one was for cruise control.
Thank you for that info. Looks like I will have to try and find one with 2 ports. Bummer! :cry:
 
Status
Not open for further replies.

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact [email protected] for info on becoming a sponsor