What the Heck are these???

[DBear]

this is my '71 burb, and at the rear on the driver's side, past the filler neck area are these three hoses/hardlines going into the side underneath. What the heck are these and what do the do?

[jbclassix]

vent lines for smog I believe.

[mosesburb]

They are for the vapor recovery system. One line should go toward the front and end at the charcoal canister. It separates liquid and vapor.

You will not use it with a diesel. A diesel tank is vented with a fitting just like a differential uses (like the ones I used on the vent lines that end up on my firewall).

[THE DRIVER]

Originally Posted by mosesburb

They are for the vapor recovery system. One line should go toward the front and end at the charcoal canister. It separates liquid and vapor.

You will not use it with a diesel. A diesel tank is vented with a fitting just like a differential uses (like the ones I used on the vent lines that end up on my firewall).

If I am removing all the smog stuff from the Burb, do I still need these? If, not what is safe to remove?

[Bigdav160]

No and Yes

[LockDoc]

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I think Bigdav misread your last question. You can remove it all and plug the extra outlets but you will have to be sure and use a vented gas cap or your engine will die after driving a block or so.

Edit: After thinking about it for a few minutes I think one of those lines comes back up to the top of the filler tube as a vent so that the gas doesn't "Burp" back out as you are filling the tank. If so I would leave that one....

LockDoc

[franken]

Emission reducing parts have a negative connotation and the to remove desire them is common. Some bits do no harm (to performance) and others are beneficial.

So, if a smog bit does no harm and reduce emissions, why remove them?

PCV (which is actually a benefit) and the charcoal canister are a pair of things that should be kept...

[LockDoc]

Originally Posted by franken

Emission reducing parts have a negative connotation and the to remove desire them is common. Some bits do no harm (to performance) and others are beneficial.

So, if a smog bit does no harm and reduce emissions, why remove them?

PCV (which is actually a benefit) and the charcoal canister are a pair of things that should be kept...

I have found that 90% of the charcoal canisters found on these trucks today are inoperable. After 40 years of neglect the charcoal in the canisters is a solid mass instead of granules, in which case would be of no benefit. If you remove the canister and shake it you should hear a rattle type sound... no rattle= no good. There was a thread on here a year or so ago and I think one of the posters found a source for a canister that would work on our trucks or the charcoal granules to refill them. A search might turn up the thread.

LockDoc

[68 TT]

Originally Posted by franken

Emission reducing parts have a negative connotation and the to remove desire them is common. Some bits do no harm (to performance) and others are beneficial.

So, if a smog bit does no harm and reduce emissions, why remove them?

PCV (which is actually a benefit) and the charcoal canister are a pair of things that should be kept...

Same goes for the EGR valves. When functional they will let you run more timing and make the engine more efficient but many are inoperative after 40+ years.