A/C & heater control vacuum line info

Gonzo1970

Gonzo1970

Greasemonkey
Supporting Member
Sep 30, 2018
224
220
43
#71
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
 
MrSony

MrSony

Comic Book Super Hero
Nov 15, 2014
4,266
2,588
113
Des Moines, Iowa
#72
You will hear a leak as well when you switch it from on to off, be aware of that. Just the system "powering down".
 
Longroof79

Longroof79

Geezer
Oct 14, 2008
9,688
5,347
113
Gainesville, Fl
#74
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

Gonzo1970

Greasemonkey
Supporting Member
Sep 30, 2018
224
220
43
#75
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
 
uneek1976

uneek1976

G-Body Guru
Jul 24, 2009
603
40
28
Sugar Grove IL/ Chicago
#76
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

MrSony

Comic Book Super Hero
Nov 15, 2014
4,266
2,588
113
Des Moines, Iowa
#77
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.102543
 
uneek1976

uneek1976

G-Body Guru
Jul 24, 2009
603
40
28
Sugar Grove IL/ Chicago
#78
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

MrSony

Comic Book Super Hero
Nov 15, 2014
4,266
2,588
113
Des Moines, Iowa
#79
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.
 
uneek1976

uneek1976

G-Body Guru
Jul 24, 2009
603
40
28
Sugar Grove IL/ Chicago
#80
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:
 

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