Vacuum S line 280z

[MH77280Z]

Guys two questions:

1. in pic#1 the S vacuum line connects to the control assembly inside the dash. There is some sort of a check valve in pic#3 mounted right under the magnetic valve where this line connects per pic#2. I assume it is the smaller end facing towards the firewall where this S line connects too?

The other end bigger end will connect to magnetic end D and M via 3-way line. Is my understanding correct?

Also, does it matter if the S1 and S2 lines on the vacuum tank are reversed?

[Yarb]

Per the diagram it looks like S1 goes to the engine side.

[MH77280Z]

2 hours ago, Yarb said:

Per the diagram it looks like S1 goes to the engine side.

Is there some kind of machanism inside this vacuum tank? i assume u mean vacuum tanl S1 and S2 cannot be reversed. I am trying to figure out the orientation of the tank to make sure S1 and S2 are at the right location.

Per my pic, i assume my S2 is connected to S1 on the tank which is wrong correct?

[Yarb]

Two separate ports per the diagram from what I see.

[Zed Head]

They can be switched.  There's no mechanism inside the tank.

The check valve is important though.  Be careful with the hoses, they are an odd size and tend to split because they're so old.  I spent a lot of time fixing mine, as they kept splitting at the ends, then the check valve went bad.  Overall, it was a pain keeping everything working right.

[cgsheen1]

When running, the intake manifold is a vacuum source but depending on the engine load the amount of vacuum can vary wildly. The check valve prevents the intake manifold (engine) from sucking the vacuum BACK OUT of the bottle when the engine load is high and/or the intake manifold vacuum is reduced. It's important that the vacuum bottle keeps enough vacuum to run all the vacuum solenoids. The check valve is a huge part of that.

[MH77280Z]

38 minutes ago, cgsheen1 said:

When running, the intake manifold is a vacuum source but depending on the engine load the amount of vacuum can vary wildly. The check valve prevents the intake manifold (engine) from sucking the vacuum BACK OUT of the bottle when the engine load is high and/or the intake manifold vacuum is reduced. It's important that the vacuum bottle keeps enough vacuum to run all the vacuum solenoids. The check valve is a huge part of that.

That’s what I was trying to confirm. The check valve pic I posted show the bigger side facing radiator. On the inside is the smaller end. Per FSM pic I assume the bigger end connect to the 3-way connector on the solenoid and smaller goes to S towards the dash through the firewall. Don’t want to connect this one reverse!!! Can someone confirm.

Edited 8 hours ago by MH77280Z

[Yarb]

Just try it and see. You are not going to damage anything. You have gotten good advice so far. Analyze what you have and give it a try.

[Zed Head]

The check valve is designed to let air pass out of the bottle and in to the intake manifold, (darn it, I knew I'd do that), but not from the manifold to the bottle.  The hose with the check valve is the one that loops around to the tiny nipple on the top of the manifold.  Suck on the valve to determine which end points toward the manifold.

Edited 6 hours ago by Zed Head
still wish we had the option to cross out text. all of the other forums have it in the Edit screen. Edit is where it makes the most sense.

[MH77280Z]

I figured, i accidentally thought that grommet is the valve …

so the manifold connects into smaller end - bigger goes to S1 in the vacuum tank. S2 from the tanks goes to the solenoids. 

[siteunseen]

My early '77 doesn't have that bottle, just the charcoal cannister. Anybody Anyone know what year they started using those bottles?

@Zed Head the cross out text isn't the same as strikethrough? 

[Zed Head]

Yes, it's strikethrough.  Couldn't remember the name.  It's here in the first box, but not the Edit box.  Weird.

I had one on my 76 but maybe it's an AC system only thing.  I had AC.