[1971455HO]

I'm a little worried here. Don't want a fire. I just discovered that my gas tank has way too much pressure in it. The pressure is forcing gas out of the top of the tank seal (somewhere) and leaking down under the tank. Not a lot, but any is a concern. I have checked the connections on the vent piping. It must be connected wrong. The guy who restored my car has not tied the charcoal canister into the loop at all. It's just mounted up there with no hoses attached at all. Isn't there supposed to be a hose connection between the vapor/liquid separator behind the back seat and the underhood charcoal filter in the engine compartment that connects to a vacuum port on the engine? How else can the tank stay stay unpressurised. I think it is totally capped off and can't de-pressurize.

This is a little scary, I gotta get this fixed.


thanks,
Eddie

[Formulabruce]

On your car, the pipe running up the Drivers side and comes up on the Drivers side Inner fender,( by the brake prop valve) goes to rubber,( across the inner fender) then to a "restricted" pipe that goes under the radiator at the rearward part of the fan shroud. This bolts to the factory clips on the bottom of the fan shroud. It comes up on the passenger side, and up by the canister. Rubber hose from it , to the canister. This line will relieve pressure slowly through the canister, which is hooked to your Q jet. Many times people toss this line or plug it off. It is supposed to be restricted and its hard to blow through, but it can be done. This will vent excess tank pressure.
This line is Supposed to have restriction, and it can be seen in the assy manual as side ways lines across this line. I have had many out and even tried to clean them out in the past.

[1971455HO]

Originally Posted by Formulabruce

On your car, the pipe running up the Drivers side and comes up on the Drivers side Inner fender,( by the brake prop valve) goes to rubber,( across the inner fender) then to a "restricted" pipe that goes under the radiator at the rearward part of the fan shroud. This bolts to the factory clips on the bottom of the fan shroud. It comes up on the passenger side, and up by the canister. Rubber hose from it , to the canister. This line will relieve pressure slowly through the canister, which is hooked to your Q jet. Many times people toss this line or plug it off. It is supposed to be restricted and its hard to blow through, but it can be done. This will vent excess tank pressure.
This line is Supposed to have restriction, and it can be seen in the assy manual as side ways lines across this line. I have had many out and even tried to clean them out in the past.

Thanks Bruce,
I'm on it. I'll have to familiarize myself with the hookups between the tank and the line running on the left side of the car. I've been hearing these strange low tone moans and groans coming from the car when i would park it. Now I know it was pressurized and finding somewhere to go. Now I'm relieved (pun intended)

Thanks a lot for letting me know.

Eddie

[giles]

Eddie,
The gas tank should have three vent ports, each has a hose that runs to the liquid separator behind the rear seat back. A hose exits the separator and connects to the steel line running up the left side of the car, as formulabruce states, then on to the canister on the rad support. The cap is sealed when you have an evap canister and the only place for vapor to vent is to the canister. Then the canister is purged via the vacuum lime to the carb.

[1971455HO]

Thanks guys,

Everything you said is totally correct. I dug out my assembly manual (section 8) and got familiar with how it should be. I have one little problem.

One of the two guys I hired to do my body work, removed the vapor line on the drivers side and it did not get replaced. I suspect it was the first guy, but don't know for sure. I'll be getting that took care of. Meanwhile, I think I can run a vented gas cap until I get it hooked up right.

Thanks for the help.

Eddie

[Formulabruce]

If you need pics of the line running up the DS, let me know. I do not know if this is reproduced. Good luck

[1971455HO]

Originally Posted by Formulabruce

If you need pics of the line running up the DS, let me know. I do not know if this is reproduced. Good luck

Thanks Bruce,

I have my service manual and my assembly manual for my car. They have pretty good illustrations. If you have better pictures, I’ll be glad to have them.

I looked at inline tube's online catalogue. They offer all the lines for around $125 + shipping. I'm gonna call them to discuss the lines that connect to the rear separator.

[1971455HO]

I got all my emission lines ran this weekend from the gas tank forward. It was a little tough, considering brake lines & fuel lines are among the first thing bolted to the bottom of a car. A little tough to get past all the obstacles. Luckily, I ran miles of instrument tube over the 30+ years I did construction, so I knew how to cheat.

I'm almost finished except I need a little help from you guys. I had clips for everything but the last tube that crosses under the radiator and goes to the charcoal cannister.

It takes three (single tube type) clips to fasten and support it. I temporarily have a wrong double tube clamp holding it in place next to the cannister until I get the right one for it.

One more thing... I'm not really sure as to the exact placement of the clips. I have spotted two holes down under the shroud on the steel radiator support that look exactly like that is where they go. But I'm not sure. They look to thin for a threaded bolt connection. Maybe it's a sheetmetal screw type clip???

Would anyone please post a few pics of this area for me with their tube installed on their car, especially the clip that holds the tube. I went through all of NJSteves thread for his '72 hoping to see something definitive. It helped but nothing as to what kind of clip and where they go.

Sorry for the long read. If anybody has three to sell, I'll take 'em. I need bolts too. My car is a '71.

Thanks,

Eddie

[dpoltzer]

1971, anyway you can post a picture of the routing of the liquid separator hose routing? I am working on a 1971 and there are 4 lines coming out of the separator but only two "Extra" lines on the gas tank. I am unsure what hose goes to where? Thanks. Dave

[1971455HO]

Originally Posted by dpoltzer

1971, anyway you can post a picture of the routing of the liquid separator hose routing? I am working on a 1971 and there are 4 lines coming out of the separator but only two "Extra" lines on the gas tank. I am unsure what hose goes to where? Thanks. Dave

Sure, I'll be glad to help you. I just now saw your post. it's a 1/2 hour past midnight right now. Been a long time since I posted any pics but I'll get you what you need.

I'll take a quick look and see if I have anything already in one of my folders that will clarify what you need to do. It's really simple once you see it.

[dpoltzer]

Thanks Much 1971! Dave

[eaglesan13]

I pulled these pictures off the internet a long time ago, and they are what I used as reference to replace the missing vapor hoses on my 1971 Trans Am.

[dpoltzer]

Thanks Eaglesan, I will look at this tonight to see if I can figure this out. Dave

[dpoltzer]

You were right and it is quite simple. The pictures were just what I needed. Thanks again. Dave

[1971455HO]

Originally Posted by dpoltzer

Thanks Much 1971! Dave

Hello Dave, sorry to take so long getting back to you. My computer was crashing for days and my folders were corrupted. It's fixed now and I can open my folders. However I see eaglesan13 has already given you what you need and his pictures are better than mine. (I'll be stealing these for my own reference...so should you.!

Anyway, let me give you some hands on for what you see.

His second picture shows the liquid/vapor separator connections. Note there are two separate openings while facing it. One on the far left & three on the right for a total of four. I'm going to call them (left to right) connection 1_2_3_4

1. The one in the opening on the far left by itself goes to the tubing on the drivers side that is fastened along with your brake line. they travel all the way to the front of your car. The vapor line travels up the driver side firewall. It then changes back to hose and continues across your left fender well and turn down and goes back to tubing where it crosses under your radiator and comes up to connect to your CHARCOAL CANISTER via hose again.

2. The left one of the remaining group of three connects to the top vent tube connection on top of your gas tank. (DRIVERS SIDE).

3. The center connection of the group of three goes to the (WHILE FACING GAS TANK) right hand or inboard connection on top of the tank. (PASSENGER SIDE)

4. The right hand connection of the group of three goes to the (WHILE FACING GAS TANK) left hand or outboard connection on top of the tank. (PASSENGER SIDE)

There are lengths of pre-bent tubing for making all these connections with the exception of the hose going to the upper driver side vent (it is hose all the way to the connection). If you don't have your original pre-bent tubing, it is available with several different vendors.. You only need short rubber pieces for most of the connections. The complete gas tank/liquid/vapor separator emission tubing, hoses & clamps can be bought as a kit.

Hope I said it clear enough. Study the pictures & diagrams eaglsan13 sent you.

Good Luck,
Eddie

[1971455HO]

Dave,

Here's a little info on the tube and hose routing under the hood for the charcoal canister. This may be somebody here on the forum??? I can't remember.

Note the steel tube emerging out from under the radiator shroud turning up across the frame rail and going to the canister.

My tank kept build up pressure too. I mean it would set and moan after being drove on hot days. I couldn't figure out what was wrong until I checked the canister. Mine had been disconnected for years and the dirt daubers had it plugged up solid with mud. I used cutting torch tip cleaners and water until I dug enough of it out to get it to blow clear. I set the air pressure to 10 psi so I didn't bust anything.

[Formulabruce]

I added to your picture as the line Under the radiator is a factory restricted line. You cannot easily blow through it. This controls the gas tank pressure at the canister. The restriction is UNDER the radiator in this line and its unrestricted back to gas tank on the Drivers side.

[1971455HO]

Thanks Bruce, glad you did.

[dpoltzer]

1971; outstanding description and Pictures! Thanks so much I really appreciate it. BTW, what color is your interior and is it a 4spd or Auto? Reason I ask is that I also owned a 1971 T-A, white, with std. black interior, no a/c and a 4spd. I always wanted to see that car again as I owned it from 1978 to 1992 until I sold it and it went to N. GA area. Dave

[1971455HO]

Originally Posted by dpoltzer

1971; outstanding description and Pictures! Thanks so much I really appreciate it. BTW, what color is your interior and is it a 4spd or Auto? Reason I ask is that I also owned a 1971 T-A, white, with std. black interior, no a/c and a 4spd. I always wanted to see that car again as I owned it from 1978 to 1992 until I sold it and it went to N. GA area. Dave

Eaglesan13 provided the good pictures for you, I just put some words with them.

My car is White w/Med. Blue Interior, Automatic, A/C, AM/FM Stereo, 8-Track, Rear Window De-Fog, Pwr. Trunk Release. I assume they all came with Pwr. Brakes & Pwr. Steering???

I traded a 1950 5-window cab SWB Chevy Truck & $1,000 for it back then and never looked back. I've owned her since Nov. 1979. It sold new Sept. 1970 in St. Louis and had migrated to Chattanooga by 1979.