Autopsy of removed plastic fuel lines, Plastic fuel lines == bad thing Options

[bperry]

As I'm doing a bunch of work on my 74, I decided to replace the original
plastic fuel lines with some stainless lines. I am amazed that these
plastic lines are still working and that they hadn't cracked given their age.
The plastic lines seemed kind of hard but I didn't think much about it
other than I never really liked them.

So I get everything loose and get ready to pull the lines and had to pop
the plastic lines out of the plastic keepers on the firewall, and CRACK,
the return line shattered and cracked right where the line starts to go up
towards the engine shelf.

After I pulled the lines, I carefully examined them and noticed that the plastic
inside the tunnel seemed to still be soft and bendable; however, the plastic
beyond the firewall in the engine compartment was very hard and the closer
you get towards the corner were the heater tube is, the more brittle the lines
get.
In my situation, the more brittle line was actually the return line which would
be the absolute worse line to break since the pump would continue to pump
fuel even after the line broke.

Anyway, I have attached some photos showing what I noticed.
I am now a believer like Clay in removing and getting rid of those plastic lines.
At this point I question why anyone would continue to use the stock factory lines.
It is only a matter of time before they cause a problem.
Luckily for me, the break happened while I was actually replacing the lines.

--------------------------------------------
A few notes on Clays Technical Article:

It would be useful to tell/show folks the 2 places where the lines are
attached inside the tunnel. One is under the shifter, the other is directly
under where the wire harness enters the cabin just in front of the
access panel by the firewall. Both of these need to be loosened
before the lines can be removed and its not particularly easy to do.

One tip I learned is to make sure that both ends of each line is open and blow some
compressed air through them PRIOR to removal. This will ensure that there is
no remaining fuel in the lines to spill inside the tunnel. - Guess how I figured out this one.....

Another tip that I've read about and intend on doing relates
to if there is concern about rattling of the lines.
The tip is to slip the tubing through heat shrink tubing has you install the
lines. Nice and simple and should be effective.

--- bill

Autopsy Pictures follow: