'70 Vacuum Canister

[69GMCLonghorn]

I'm tearing into my '70 C10 Custom and discovered a capped off vacuum canister tucked in the front fender well. There is one line back to the tank that is still run, but 2 others that are just cut. Although it's technically a smog device, it really doesn't rob power. Should I rerun the lines or just yank the whole thing out and be done with it? Opinions please!

[71K20chevy]

That is the charcoal canister, you can remove it and cap it off as long as you put a vented fuel cap on.

[cdowns]

if it is in fact the charcoal canister you have got a 71-or 72 front clip on it as they did not have charcoal canisters in 70// i'd check the vin numbers on the frame to see if they match your vin on the door

[69GMCLonghorn]

Originally Posted by cdowns

if it is in fact the charcoal canister you have got a 71-or 72 front clip on it as they did not have charcoal canisters in 70// i'd check the vin numbers on the frame to see if they match your vin on the door

Well ain't that nice... The front end is 1970, and the whole thing looks really unmolested in terms of dirt, etc... But who knows what's been done over the past 40 years... I'll have to check it out.

[ray_mcavoy]

I think California required those canisters earlier than the rest of the country. So that could very well be original to your '70.

You're right, it doesn't rob any power. So if you decide to hook it back up, those other two lines just go to the engine/carb. If I remember correctly, the larger one T'ees into the PCV vacuum line. And the smaller one is a purge control valve that connects to a ported vacuum source on the carb.

[70STOVEBOLT]

What is the effect if you cap it off and do not install a vented fuel cap? I have one and it has been capped off since I have owned the truck and I am running the original fuel cap. A problem that I have is that the fuel runs out of the bowl after about 10 minutes after shut down. I also have one hose still hooked up to the steel line on the frame rail. Could this be the cause of the problem?

[LockDoc]

70STOVEBOLT:

It probably does that because it is creating a vacuum in the tank because the cap isn't vented and the vacuum is sucking the fuel back into the tank when it sits... I don't think it could suck it out of the bowl but it could suck it out of the line.

69GMCLonghorn:

If you take the canister out and shake it and it doesn't rattle it isn't any good anyway. I have heard that you can put new charcoal in them but I have never tried it. If you type "charcoal canister" into the Google search box at the top of this page, click the circle in front of "67-72chevytrucks.com" and click on the Google button it will bring up some threads about it.

LockDoc