Vintage Mustang Forums banner
Cancel
Create thread New Garage Forums

1967 Vacuum canister issue

Jump to Latest
1 - 20 of 20 Posts

LaPorta

· Registered
Joined
·
1,527 Posts
Discussion starter · #1 ·
Now that I got my whole heating and AC system back together, I realized that there was no vacuum actuation. So, I checked at the manifold and I have decent pressure there. I checked at the hose from the manifold to the tank, at the far side of the check valve, and I have the same vacuum reading...so the check valve isn't backwards or anything. With that hose connected to the vacuum canister, I checked the other end of the canister...and detected no vacuum. I'll double check, but I assume that figures that my tank is bad. Unfortunately, mine is an early 67 with the tank mounted in the engine bay. It seems that this tank is not reproduced as the latter, inside the fender one is.

How do I go about checking this more thoroughly? Is there any way to repair these tanks? How exactly do they work, anyway?
 
#2 ·
I have that same set up. Early October of 1966 built car before they moved it to under the battery. Vacuum test that tank. If it is sucking air, and the holes are small you might be able to seal it with carefully layered Flex Seal.
I did buy a good used southwest tank on Ebay some 8 years ago. Check there too.
 
#4 ·
If your can is bad you may be able to make one by going to the store and see if you can find a tin can of juice or any liquid that is about the same size. Then all you have to do is poke a hole in it with an icepick and drain it then add the fittings off your bad canister. You may have to fabricate some stuff but I would attempt this purely out of fun!!
 
Save
Reply Quote Like Like
#5 ·
The used vacuum can I bought had several small rust holes in it. After cleaning the bottom I filled it in with JB Weld. Hasn't leaked in three years.
 
owns 1956 Ford F100
View garage
Save
Reply Quote Like Like
#8 ·
If the holes are small I would solder them up rather than use something like JB Weld or a sealant. I always prefer solder when I can use it to make or fix something. It is a tool people seem to overlook these days because it is harder than magic in a can, but it is far more permanent and does not look out of place.
 
  • Like
Reactions: mustang1969
Save
Reply Quote Like Like
#9 ·
You do you bro. Any repair on the vacuum can will look "out of place". Butt no one will ever see it since it's behind the the inner fender on the wheelhouse.
 
owns 1956 Ford F100
View garage
Save
Reply Quote Like Like
#10 ·
LaPorta said:
Now that I got my whole heating and AC system back together, I realized that there was no vacuum actuation. So, I checked at the manifold and I have decent pressure there. I checked at the hose from the manifold to the tank, at the far side of the check valve, and I have the same vacuum reading...so the check valve isn't backwards or anything. With that hose connected to the vacuum canister, I checked the other end of the canister...and detected no vacuum. I'll double check, but I assume that figures that my tank is bad. Unfortunately, mine is an early 67 with the tank mounted in the engine bay. It seems that this tank is not reproduced as the latter, inside the fender one is.

How do I go about checking this more thoroughly? Is there any way to repair these tanks? How exactly do they work, anyway?
Click to expand...

Pardon Our Interruption...

www.ebay.com
 
#11 ·
Do there early tanks have the check valve in them? I have a late fender mount with integral check valve so I don’t know.

Just fyi as long as you aren’t driving or messing with the gas you should be able to bypass the tank and everything work. The tank was to provide reserve when you nail the gas.

as suggested you can use a mityvac to produce vacuum (keep pumping it) and work all your ac doors. I tested all mine before reinstalling.
 
#13 ·
News: on the early built 67's, that bolts onto the inside of the engine sheet metal through the two holes below the right hood hinge. Make it really hard to readjust the hinge with the tank on.
 
#14 ·
I have an early 67 built in October 66 that has the tank mounted next to the hood hinge. Test the tank by plugging one of the inlets, then plug a Mighty Vac on the other inlet. If it holds vacuum, it's good. My original would not hold a vacuum and was not repairable so I purchased a good used one from West Coast Classic Cougar.
 
Discussion starter · #16 ·
So actually an interesting result: the tank holds vacuum. I used a manual vacuum pump to the tank with the other end plugged, and it held without wavering. Good deal. What I don’t get is why if I apply vacuum with the pump to the tank (or, bypassing the tank entirely, as I tried), nothing happens with the AC vacuum system. Not so much as a budge of any of the actuators no matter what position the switch is in. No matter how I move the switch, the amount of vacuum in the tank doesn’t budge. Is it possible there’s something wrong with the AC control panel, or it is plugged somehow?
 
#17 ·
La Porta:

I'm working on the same situation as you with my 67 with factory air. I used a Mighty Vac to test the A/C vacuum lines under the dash and the vacuum motors. Here's the diagram I used:

Image


Where the black line from the reservoir connects to the Tee (Purple line), I disconnected the black line from the left side of that Tee that goes to the AC vacuum system, applied vacuum using a Mighty Vac and it will not hold vacuum on any setting. Purple line holds vacuum all the way to the water valve. All vacuum motors tested fine and hold vacuum. All vacuum line connections are good. I'm suspecting the seals in the A/C vacuum control has failed.

Since I am bypassing the heater core due to the heater core leaking (and I live in Tucson, AZ), as a workaround I disconnected the black line from the reservoir at the Tee and plugged it directly to the A/C-Heat Door Motor so the air blows through the dash vents instead of the floor vents. I also disconnected the white line from the Outside-Recirc Door Motor, manually pushed the motor in to simulate vacuum and put a vacuum cap on it. This way I have Recirc A/C blowing through the dash vents.

I'm in the process of figuring out what I am going to do with the A/C controls. It was 112 here yesterday, I need A/C working while I figure this out some more.
 
#18 ·
I have found at least two A/C controls that leaked, so it seems to be a common Problem. LUCKILY I had three and the last one works as designed.

Vacuum Switch - A/C - Used ~ 1967 - 1968 Mercury Cougar / 1967 - 1968 Ford Mustang

Also it is common to have a failed or missing vacuum check valve in the system. In early 67 with the canister under the hood hinge, the check valve goes between the manifold and the vacuum canister. In late 67 & 68 the check valve is built into the vacuum canister mounted under the fender, however I have not found one (original or repro) that doesn’t leak so I use an inline one like the early 67 used. Most available are cheap plastic and don’t look right or leak. WCCC reproduced the originals with a Concours level high quality (and price) piece. They come with a lifetime guarantee! They are also used on the Tilt Away Column if you have one. I put one in and haven’t had an issue since.

Check Valve - Headlight / Tilt Away Column Vacuum System - Repro ~ 1967 - 1970 Mercury Cougar / 1967 - 1973 Ford
 
1 - 20 of 20 Posts
About this Discussion
19 Replies
9 Participants
Last post:
Flade
Vintage Mustang Forums
posts
4.2M
members
101K
Since
2001
A forum community dedicated to vintage Ford Mustang owners and enthusiasts. Come join the discussion about restoration, modifications, NOS parts, troubleshooting, VIN codes, and more!
Full Forum Listing
Explore Our Forums
General Vintage Mustang Forum Mod and Custom Forum Want Ads Concours Forum Build Forum