What is this thing called?

[Steve W]

So, I was tuning up my 68 CdV, new wires, new plugs, new rotor, new cap, already has the Pertronix points-eliminator module (Igniter 1) from 10 years ago or so... and I was doing the timing, I had blocked off the at the distributor and capped the port at the carb, disconnected and capped the vacuum that goes to the brake release on the neutral safety switch, and plugged my vacuum gauge into the open port pictured.

In the picture, you'll see it has one inlet on the left from the manifold, two ports on top, one out the right side, and it's SUPPOSED TO have one port below...which feeds the brake release on the neutral safety switch... but it broke off!!!

I'd like to replace this part, but I don't know what it is called.

Anyone??

[Roger Zimmermann]

Vacuum manifold?

[TJ Hopland]

The round part on the one end has to be something.  The rest doesn't look big enough that its a vacuum controlled valve so maybe the round part is a check (one way) valve? 

[Steve W]

Right. I've been doing a bit of research, and Roger is correct... Vacuum Manifold. On the left, it's connected to the intake manifold behind the carb. On the right it goes, I think, to the vacuum storage can, which is why it has a check valve? The other ports are for the a/c controller in the dash, the parking brake release, and I guess other accessories like power door locks and trunk (which I don't have).

[V63]

They get age cracks (then leak vacuum) and I have had luck coating them with clear epoxy or catalyst clear.

[Steve W]

They get age cracks (then leak vacuum) and I have had luck coating them with clear epoxy or catalyst clear.

Good idea! Unfortunately, the bottom port nipple broke completely off on mine. I simply tapped a screw into it for now and re-routed the parking brake line to the top left port.

[Steve W]

So...in researching it, I've come across TONS of info for the vacuum thing that's off the front of the head that goes to the vacuum advance and has multiple ports for...whatever (mine has been disconnected since before I bought it). But nothing for what I'm actually looking for. Anyone know where I should look?
Also...I guess while I'm at it, I should replace most of my vacuum lines that are in the vicinity of the intake manifold, carb, the one that goes to the trans, and this thingy. Looks like there are a few different sizes of vacuum tubing. Anyone know what sizes these are? Or is there some sort of "kit" that has all the different vacuum lines?

[Steve W]

Anybody?

[Daryl Chesterman]

Caddy Daddy has this generic kit.  I used it to replace all of the vacuum lines under the dash on a 1959 Deville, and most of the ones in the engine compartment. There was plenty of hose to do the job.  I don't know if it will include all of the vacuum hoses in the engine compartment that you need because there are more in 1968 than there were in 1959.

     https://www.caddydaddy.com/1959-1960-1961-1962-1963-1964-1965-1966-1967-1968-1969-1970-cadillac-vacuum-line-hose-kit-7-colors-8-pieces-reproduction-free-shipping-in-the-usa.html

Daryl Chesterman

[Steve W]

So...I was changing the vacuum lines today, and even though I was being very careful, I snapped off another fitting on that firewall-mounted  vacuum manifold. I guess over the decades, these things just get extremely brittle and break off very easily. This time it was the fitting on the left, the main one that leads to the engine intake manifold. I was able to use a little plastic brake bleeder adapter fitting to wedge into the hole, and run the line to the intake manifold, so it works...for now. But I really have to find a replacement vacuum manifold or figure someway to fix this one. Any ideas?

[Gabe Davis]

Perhaps something like this could be adapted to work? Maybe add a vacuum check valve where needed.

https://www.dormanproducts.com/p-27798-47361.aspx

[Steve W]

Perhaps something like this could be adapted to work? Maybe add a vacuum check valve where needed.

https://www.dormanproducts.com/p-27798-47361.aspx

I might just have to do that. And yes, I'd have to be add a check valve. Hmmm are check valve's directional?

[V63]

The device on the cylinder head  you asked about earlier is a "thermal ported vacuum switch" (vacuum control) it has a temperature sensor in it and directs  vacuum accordingly.

[colorado4x4]

It is called a vacuum check valve. 

It's one of those unobtainium items that are some of the first things I look for when a 1970 Cadillac shows up at the boneyard.  Here are some photos and descriptions that may help you.  John Abend on FB posted about these valves, the narrative I have included as a screenshot.

They tend to be very fragile.  I have a couple of them that need repairs also. I was thinking of getting one of those black plastic vacuum tees at the the auto parts store and cutting one of the ends off and slightly grinding the edge of the tee and then, using a drill bit, slightly cut a concave impression on the vacuum check valve at the broken tee and then gluing them together with JB weld or something.

[Steve W]

Colorado 4x4, this is great! Thank you so much for posting all this!

After a great deal of searching and sending numerous emails and messages, I was able to purchase a NOS unit that will arrive here on Monday.

It'll be kind of difficult to install with only one remaining arm and leg 🤪 but I'll manage somehow! (yeah, it was a little pricey, but unobtainium usually is!)

[Steve W]

Installed! I had to replace the vacuum line to the NSS, because the section that was in the engine compartment was so brittle, it would just split and crumble. The other lines were fine though. Now, everything works as it should!