vaccum canister on 81

[gravismaximus]

vaccum canister on 81, where is it sopose to be, whats it look like, does it even have one?

on my 81 there apperas to be a painted coffee can mounted with brackets in between my headlights. vaccum lines run from the headlight actuators to this canister back to the switch from the manifold or someway like that. anyway a coffee can looking canister on a vette????:eyerole and i cant find anyrefrence to it in the shop manual. could someone please send me the actual vaccum line routing for the headlights or just what hooks up to what in order from the switch forward. thank you... coffee can:crazy

 

[LannyL81]

The best diagram is found in the Assembly Manual

But here is my description from memory.

The vacuum source is from the intake manifold between the carb and the distributor. From the intake the vacuum line goes to a check valve and then to a 1-2 splitter.
One line from the splitter goes into the firewall and then to the vacuum over-ride switch. There is a line that goes from this switch to the headlight switch. And then a line from the headlight switch back out through the firewall.
The other line from the splitter goes to a "T". The small line at the "T" goes over to the passenger side of the distributor, and into the firewall, into the wiper tray area, then down inside the fender.

The larger line at the "T" and the small line from the dash go forward to the headlights. The small line goes to the vacuum relays, two of them. This controls the switching of these relays.
The larger line goes directly to the vacuum canister.
From the canister are two large lines that go to the middle port of each vacuum relay. There are two other lines on each relay that go to the headlight actuators, one for closing, one for opening.

Prime area for leaking is at the canister connections and the canister itself.

Hope this helps.

Later,
LannyL81

 

[gravismaximus]

thanks larry, it was helpful kinda, my vette is nowere near stock anymore, but im pretty sure tha if i keep the canister on the manifod vaccum side and every thing else after the canister ill be fine. i do have to say im :W about the idea that any car would use a coffe can, thou ive been told it was a common thing for the 80's. but the flagship. im gonna bet this is why the changed over to the vaccum ball, at least its plastic and wont rust from the rain.

 

[Peer81]

You're correct. It's a weird looking kind a coffee can on there top model. Here a photo from mine:

Mine had also a little crack in the can, but i can be welded so no problem.
You could also leave out the coffee can and make some vacuum connections in the front hollow tube (on the chassis extention) but first test if its really vacuum closed welded. I thought the 78 models etc also have there vacuum storage there...

Groeten Peter.