climate control vacuum lines

by michiganlarry Tue Apr 09, 2013 7:41 am

I need some help with the three vacuum lines that come into the engine compartment from the center of the firewall. I believe these are for the heater / ac controls. I didn't take a good picture of theses before the old engine came out. I am thinking that one goes to a vacuum source on the manifold and the other two go to that "ball" near the blower motor? Can anyone verify this or maybe have a picture of these lines hooked up?

Thanks again for all the help you guys have given me.

by pila Tue Apr 09, 2013 5:11 pm

I believe one of those hard plastic lines connects to the vacuum operated water valve. That line usually has a rubber end on it , with a loop, to hold it on the valve.

by Hawk03 Sun Mar 16, 2014 8:54 pm

Does anyone have a picture of the line connections? Also, is there anywhere that sells replacement lines?

by pila Sun Mar 16, 2014 11:49 pm

I don't have a picture, but usually there are two small diameter hoses and one that is a bit larger, coming through the firewall. The larger one goes the the top/rear of the intake, for manifold vacuum source, one small one goes to the water valve in the heater hose, to shut water off when AC is selected. At least that's how I remember it.
I may have a diagram for the vacuum line hook-up, I'll take a look...

Bill

by Hawk03 Mon Mar 17, 2014 10:20 am

Thanks thats helpful. I cut my lines to get the body off and I don't remember how they are and I'm pretty sure the new body dosen't have them coming from the firewall.

Anyone know the best way to repair the hoses or get new ones?

by Mcarlo77 Mon Mar 17, 2014 11:47 am

To be more specific on what goes where...there are three small hoses coming from the firewall. The one with a brown stripe goes to the water control valve. The one with a white stripe goes to the vacuum ball. Third one is fitted with a three-way hose nipple that allows a larger size hose to go to the vacuum valve on the intake manifold (as Pila mentioned) and another larger hose to the second fitting on the vacuum ball.

As for splicing, try your local auto parts store and see if they have the very small size straight-thru hose nipples.

by bitterfitter Mon Mar 17, 2014 2:41 pm

I was in the same place you are and one of the fellows on here sent me the vacuum routing for these lines. I can't post from work, but if you get me an email, it will come your way. Also I used new pieces of hose that I got from my local parts store. I think most parts stores might have them if you ask the right person. I used the small rubber hose as female couplers. Works great and no leaks!! If you are in a pinch, let me know. I may have some left I can send.

by WyldeBill66 Mon Mar 17, 2014 9:13 pm

I have this problem too. My car came to me with some vacuum lines messed up. I have heat, but I can't change it to anything else. Not even defrost. I'm sure there is no vacuum going to the control, but can't figure out how to get it there. I've hooked up vacuum to the vaccum ball, then to what I thought was the line going through the firewall with no luck. A diagram and/or pictures would be great if someone could post them.

by Mcarlo77 Mon Mar 17, 2014 10:11 pm

Here is the diagram out of my Chevrolet Service Manual for '76/'77 models. I'm sure earlier years are the same.

climate control vacuum lines G3vacu10

I was mistaken in describing the line that goes to the vacuum ball as having a white stripe. Instead, it's gray...per the diagram.

by WyldeBill66 Mon Mar 17, 2014 10:28 pm

Thank you Mcarlo77. Much appreciated.

by Hawk03 Tue Mar 18, 2014 7:58 am

Thanks guys! This helps a lot. I was afriad the lines would be harder to get, so that is a load of my mind. Hooking these up along with starting the engine for the first time is on the list for next weekend!

by Hawk03 Thu Nov 13, 2014 11:56 am

I mended my vacuum lines with a 1/16 inch hose mender from Mettle Air. I heated up the hose and installed the mender which made a good connection. I haven't tried to see if it works but there isn't any reason why it shouldn't.

https://www.mettleair.com/store/polypropylene-plastic-1-16-hose-id-hose-barb-mender-splicer-joiner-union-fitting-tubing-hose-adapter-coupler.html

by builtnotbought Sun Feb 21, 2016 4:58 pm

Mcarlo77 wrote:Here is the diagram out of my Chevrolet Service Manual for '76/'77 models. I'm sure earlier years are the same.

I was mistaken in describing the line that goes to the vacuum ball as having a white stripe. Instead, it's gray...per the diagram.

Start to sort out things with my lost vacuum pipes and realize that my 74 connector has 8 pipes instead of 7 as on the pic. And I don't have brown pipe with tee to water valve at all.

May be somebody have earlier 73-75 diagrams on photo?

Thank you

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