gto fuel tank vent tube location
 

I am installing a later 3 vent fuel tank in my 69 and I can't figure out the location of the front fuel tank vent line. The service and assembly manuals show different diagrams and neither look like the underside of my 69.

can someone tell me where to hook up a vent line?

Also, I've already capped 2 out of 3 vents. I have no idea where the third vent goes. I believe a U shaped tube hangs somewhere to vent the tank (according to the manuals) but I don't see where to mount it or which vent of the 3 to use. One 69 manual shows the vent on the RH front corner used as the vent but the diagram doesn't look like what's under my 69.

I may have to look at my car to better describe this, but the U-shaped tube goes thru the trunk at the gas tank filler. The original hose attached to the tube has "GAS" stamped on it several times and attaches to the tube/gas filler neck. The tube goes into the trunk and back out thru a rubber grommet that is reproduced. I seem to remember that the tube is held in place by a small bolt and a small gold cadmium clamp that wraps around the tube. (I have not seen a repo of this small clamp/bolt.) I'll have to look at it or take a picture if you want it "just so."

The only other vent on my 69 is at the front (towards the front of the car) on the passenger side. A tube (with 3 grooves I believe) is attached to this vent with a spring clamp. This same tube is clamped above the tank to the body of the car by a small curved clamp attached to the body with a small bolt. Your car body should have this hole tapped I assume. I have not seen a repo of the clamp that attaches to the body, but the hose/bolt could be found at an auto/hardware store but may not be exact.

I have my tank out and can eventually get a few pictures if needed.

thanks for the info. I'll look for the mounting hole for the clamp

okay I found a screw on the LH side and see an equivalent hole on the RH side - so I'll assume that the guy who took out the tank stored the screw in the wrong place. I have it now - thanks

Just to add to Bet Winner's very good description.

The forward hose that is nearest to the rear axle also has a vent material inserted in the end of the 6"-8" hose. Mine crumbled in my hand when it came out. I suppose it's there to prevent debris from entering the tank but is porous enough to allow the tank to vent properly. I've read of people replacing it with steel wool or just nothing at all.

My hose may have originally had this material in it, but I did not find it. The gas tank had never been out of the car. (I have had this car since 79.) I would be interested in seeing some of the material or hearing what it was in case I want to duplicate it.

I believe the 3 vent tank is for CA emissions car. A regular tank has a one vent on the front passenger side and one on the filler neck. To make yours work, I'd cap two of the vents. Use the one on the passenger side with a 5" hose that slides under a metal flap on the car. You might have to use a vented gas cap too, since you are missing the filler neck vent.

If he wants to use the vent at the filler neck, I believe that the important parts are reproduced. There are probably 2 holes in the trunk for the tube already there if I remember correctly.

I assume that with a vented gas cap, it will probably work to use one vent also.

Mine sort of resembled that dense green foam (but a dark gray) that people put fake flowers in, for lack of a better description. It was rather brittle due to age, so it crumbled to dust just from handling it. It is completely inserted into the hose so it is not visible.

why install the later tank in the car
68-69 bothe had one 1/2" vent at the passenger side back and a small 1/4" one on the filler neck that went to the trunk vent tube
70 had different vents one 1/2" and one 1/4" same spot in the back next to eachother that connects to the white plastic filter.
70 Calif cars had vents on each side of the tank going to a stand pipe and a filler neck vent tube
71-72 tanks also had the vents on both sides and they went to the back seat stand pipe and no vent on the filler neck.

Although the body of the tank is the same the vents are always labled wrong in catalogs. The tanks are very year specific. Emissions

I still have an original 69 front vent hose, it has a stapled in restrictor, basically a trap to hold in the fumes until pressure builds up

this one - http://cgi.ebay.com/ebaymotors/68-69...item5ad835efd8
http://i.ebayimg.com/04/!BpQ6Yj!CGk~...GDFdw~~_12.JPG
http://i.ebayimg.com/20/!BpQ6,F!!Wk~...KJ(Qw~~_12.JPG

Ahh so THATs what that retainer is for!

I see you also have the repopped vent tubes. FYI All auctions show diagrams of how to attach these.

Magicv8 said he found the screw on the left side, on my 69 that screw was used for the ground of the sending unit. I also had a 69 LeMans that had the sending unit ground there to. I also remember seeing that screw on Chevy and Olds A bodies in the bone yards. I have the clamp for the vent on the right side. That S bracket to hold the vent hose was on Chevelles also.

On my 68 the ground screw is also on the LH side.

Hopefully I'll be able to fully install my fuel tank in a week!

See pics below. First is the routing of the two vent lines to the factory fuel check valve (white cube) and the single vent tube that runs over the tank yo the rear of the car. I also have the 3 vent tank and just T'd the driver side corner vent into the larger vent line before the check valve (not shown in the pic). You will find the recess for the valve and a stamped hole already there on the frame to clamp the valve with the strap. The strap is usually sold separately from the valve..

The outlet side (top of the valve) attaches to a hose running over the top of tank that connects to an overflow fuel stand-pipe installed in the trunk above the fuel filler neck. There should be a knock out in the floor for the tube and grommet of the trap.

'69-70 uses the short standpipe, '66-67 the longer one. A clip and self tapping screw attach it to the trunk lock brace on the rear header panel.

'70 fuel vent lines and vent valve
https://imagizer.imageshack.com/v2/3...922/rESQKl.jpg https://imagizer.imageshack.com/v2/3...924/tv8WJr.jpg

'70 (Short) & '66-67 (Long) Vent line standpipe
https://imagizer.imageshack.com/v2/3...923/pkw9H4.jpg https://imagizer.imageshack.com/v2/3...922/C3g6Sa.jpg

Standpipe in trunk
https://imagizer.imageshack.com/v2/3...924/IdXYQg.jpg

Diagram for 69 tank front vent tube on passenger side shows the hold down clip screwed in to the gas tank trunk support brace.I dropped my tank to replace it,and found that there are no holes in the brace to screw the bracket to.Checked the other brace and nothing there either.Trunk pan was replaced by one of the previous owners,and I'm assuming braces were replaced also,because of the missing hole for the vent bracket.So question is,does the diagram show the correct location?And shouldn't there be 2 holes,one for the locating tab on bracket and one for the screw?