Vacuum lines to “water valve”, why are there 2 of them?

289 - 351 cid Small Block Performance
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67CalienteRestoMod
Posts: 8
Joined: Tue Apr 28, 2020 7:22 am
Location: New Mexico

Vacuum lines to “water valve”, why are there 2 of them?

Post by 67CalienteRestoMod »

I bought my ‘67 Comet with a bypassed heater core and half the vacuum lines to the HVAC missing. I’m fixing all that now, and have tried finding a vacuum diagram to help. Closest thing I found online is a Mustang diagram (with AC like nine). Most the diagrams I see only list 1 vacuum line to this water valve under the hood. Can someone help me figure out why there are two, and which ports get plumbed to where....?
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‘67 Comet Caliente (RestoMod in progress)
351W w/FiTech EFI, MP brakes front disc conversion, 17” Mustang wheels

‘66 Mustang Coupe RestoMod
5.0L EFI w/AOD, 4 wheel disc brakes, 17” Mustang wheels

Grandpa’s ‘69 F250 Ranger w/428FE

67CalienteRestoMod
Posts: 8
Joined: Tue Apr 28, 2020 7:22 am
Location: New Mexico

Re: Vacuum lines to “water valve”, why are there 2 of them?

Post by 67CalienteRestoMod »

In fact, the more I stare at these diagrams; maybe they aren't compatible. They all show 4 various vacuum motors, I only have 3 :?

I have one on the fresh air cowl on the passenger side.
I have one right in front of the hvac box that I presume is the defrost motor.
Then my last one is on top of the box mounted near the "ACP Vacuum switch assembly Air Conditioner/heater control" (which I am still not clear what it does). However, this switch looks just like the diagrams depiction of the "water valve vacuum switch"

Anyone have pictures or vacuum diagram that is specific to a 1967 Comet w/AC?
‘67 Comet Caliente (RestoMod in progress)
351W w/FiTech EFI, MP brakes front disc conversion, 17” Mustang wheels

‘66 Mustang Coupe RestoMod
5.0L EFI w/AOD, 4 wheel disc brakes, 17” Mustang wheels

Grandpa’s ‘69 F250 Ranger w/428FE

67CalienteRestoMod
Posts: 8
Joined: Tue Apr 28, 2020 7:22 am
Location: New Mexico

Re: Vacuum lines to “water valve”, why are there 2 of them?

Post by 67CalienteRestoMod »

Can anyone post a picture of their firewall, showing the vacuum and coolant plumbing of the water valve?
‘67 Comet Caliente (RestoMod in progress)
351W w/FiTech EFI, MP brakes front disc conversion, 17” Mustang wheels

‘66 Mustang Coupe RestoMod
5.0L EFI w/AOD, 4 wheel disc brakes, 17” Mustang wheels

Grandpa’s ‘69 F250 Ranger w/428FE

HIPOComet
Posts: 4
Joined: Sat Feb 09, 2013 9:47 am

Re: Vacuum lines to “water valve”, why are there 2 of them?

Post by HIPOComet »

The 1967 Falcon, Fairlane and Comet used a dual-diaphragm (one vacuum line to each) "blend" water valve assy. (mounted on the top of the cowl under the hood) in conjunction with a three connection heater core. This was a change from the introductory version of the 1966 selectaire system which used a single-diaphragm strait-thru valve mounted on the passenger inner fender top. The vacuum lines go thru the firewall (using rubber grommets) and are connected to the blue and yellow ports of the control valve assembly mounted behind the dash on the lever control unit. The lever operated valve should have blue and yellow paint dabs on the connection ports. Original dual-diaphragm units are comparatively expensive.
The Shop Manual (available reprinted) and/or the factory assembly manual (reprint available from Osbourne's) shows the vacuum lines connections.
I found this online; https://www.ebay.com/itm/1967-FORD-FALC ... 3187652334
Let me know if it works for you.

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