[East]

I have found one of the fuel lines pinched/smashed midway between engine and tank.

It is most likely the return line as I am getting fuel to the engine.

How hard would it be to replace the line since I am reluctant to deal with Inline Tube because of negative posts? If the posts are true, is there a different source that will have what I need?

Or could I place a repair at that spot?

[Shiny]

Is it a stock mechanical pump?

If so, the return line doesn't carry any significant fluid flow. It's more about preventing vapor lock and there is a small orifice in the pump return to limit flow.

So you might be just fine with it crushed as long as it's not totally collapsed.

[East]

The tube is smashed shut.

I have only been using the stock mechanical pump.

I don't know how long the line has been like that or how it happened. This car was my very first car that I bought in June of 1982

A while back I pulled into my garage and noticed a faint humming noise. I walked around until I noticed this sound was coming from the back of the Firebird. I traced the noise to be around the license plate. I removed the gas cap and received a gush of air.

I thought the crushed line and gas tank pressure were associated.

I had replaced the original gas cap with a locking one many years ago. It's the same cap that is still in use.

I don't have a vent tube on the filler neck, nor do I remember if there was one on the original gas tank. I had replaced the gas tank many years ago because it had a dent from the leaf spring by the previous owner in an accident.

[JLMounce]

Which year bird is this? It's my understanding that 67/68 cars should have a vented cap and the 69 cars have a vent in the filler neck. There is an up and over tube in the trunk for that.

You need the tank vented, and I would absolutely try and solve that either with a vented cap or a tank that is vented itself.

In regards to your fuel lines, if it's the return line (should be 5/16" OD) it does not really carry liquid, but instead vapor back to the tank. Replacing that line can be challenging based on it's routing, but not impossible. There are various tube benders other than in-line tube, but my experience with them has been positive.

If the line itself is in otherwise good condition and simply got smashed, assuming it is the vapor return, you could do a bush fix and cut out the smashed section and replace with a fuel safe soft line. You'd need to check on it every couple years as you do the soft line from the tank to the hard lines, but otherwise that would work fine for a non-concourse driver.

[burd]

Inline tube is fine.
Classic tube is another.

[north]

Sounds like two coincidental issues. There were two fuel tank arrangements on 69 Firebirds, early cars had a vent tube on the filler neck and a non-vented cap. Apparently they were prone to the attached hose pinching so midyear they deleted the filler pipe vent and switched to a vented cap. If you have a non vented tank with a non vented cap you are creating a vacuum in the tank. At higher sustained engine speeds you could cause engine stalling or even collapse the tank.

As for the pinched vent line, it is not critical. Cars with a 2bbl and no AC didn't even have a return line. The return line was really just (as already mentioned) to reduce the potential for vapor lock at high temperatures. If you want to fix it you could just cut out the affected area, flare it and put a bit of piping with couplings or even just some 1/4" fuel hose with two clamps if you aren't too fussy!

[tekheavy]

Never had a problem with Inline Tube.

[jwcfbd]

Like North said. Is there any reason why you can just cut out the damaged section and run a new line?

[East]

I have no problem only replacing the damaged area. I would not use rubber in the repair.

I am working on a 1969 Firebird.

I really can't remember a vent tube on the tank that was removed. I probably should look for a vented locking cap.

I do fill the tank as full as possible. I haven't experienced fuel escaping upon acceleration.

It seems like the tank is getting pressurized more than being vacuumed.

Is this related to how hot it is outside? I live in Las Vegas where summer temperatures are extremely hot.