actually a FULL gas tank is safer because of less fumes in the tank

There are four self-locking nuts on a Wal-Mart

There's one NUT right here in this newsgroup, Why, it's YOU Nomen!!!!

Please cite references for for your accusations

Without knowing the alloy and temper of the bolt, you can't know that.
Please provide a few examples of these too-high specified torques along
with what you know to be the grade of metal and recommended chart value
for that grade and thread diameter and pitch (and what the percent of
yield the chart values are based on).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

sure they do, alot of the newer chrysler products have them,,, im sure EPA
doesnt want those on the vehicles, it is hard enough just getting fuel
pressure sharader valves on most cars now, EPA screams enviroment!!!

My goodness!  You are so full of sh.t!

Ian

I've seen many early Japanese cars with such a device (Nissan Maxima,
Toyota Crown / Cressida etc).
Question is how often is it used (virtually never)   Putting a drain
on a fuel tank creates a potential leak source and requires greater
cost and added weight for the vehicle to haul around (ditto for the
dual fuel pump idea that was below).

My Personal Olds is almost 10 years old and well well over 160K still
on the original fuel pump that should have been replaced last spring
<grin>.  Every part will wear out given enough time & miles.  The
safety issue is more of incompetence and negligence on the part of the
repair shop.  

My $0.02

You are so full of $hit your eyes are brown.
NO fasteners on a car are overtorqued by design. The bolts that carry
high torque are SPECIFICALLY designed to stand that torque.

As for fuel drains on fuel tanks, yes, aircraft have them. If a drop
of water gets into the wrong place on an airplane you don't just pull
over to the side of the road. You come down.

That said, there are good reasons for NOT putting drain valves in
automotive fuel tanks. When I started in the trade, they were common.
Drain PLUGS, just like in an oil pan. Taking them out to drain fuel
was more dangerous than pulling a line and letting it drain.
The extra working of the metal, and welding in of the "boss" for the
drain caused the tanks to rust out around the drain.

On today's plastic tanks that would not be a problem, but in order for
the drain to work as a drain it MUST be at the lowest point. Retention
of the drain bolt in event of something being cought under the vehicle
is a REAL issue, unlike the straw man you arer attempting to build
around the in-tank pumps.

The tanks must NOT LEAK under any cercumstances for environmental, as
well as safety reasons.

Also, it is ILLEGAL and UNSAFE to drain fuel into an open container. A
proper, approved fuel drain unit is REQUIRED to safely drain a fuel
tank. The fuel is drawn from the sealed tank, through an air-tight
hose, into another sealed container that is GROUNDED to the vehicle
being drained to avoid any chance of a static spark.
Using this fuel drain unit, no fuel ever spills.

As for the in-tank pump - the fuel acts as the coolant for the fuel
pump. In some it is even the lubricant. The pump is always fully
submurged in fuel - either liquid of vapour. Fuel vapour is
significantly heavier than air, so even if air gets into the tank, the
pump never sees it.
The vapour pressure of Gasoline ensures the tank is virtually always
air-free. The flamability limits of gasoline ensure it will NOT be lit
by the "sparks" at the pump motor brushes.

The electric fuel guage sender unit, basically an open rheostat, is
MUCH more likely to cause a fire than the fuel pump - and has been in
use since the late twenties. Never heard of a fire caused by the fuel
guage.

Externally mounted pumps, unless engine driven and engine mounted, are
open to corrosion which can perforate the pump case, allowing it to
leak fuel. The connections are also open to corrosion - and they are
exposed to air, which contains oxygen, which gasoline requires inorder
to burn.. Also, fuel pumps are MUCH better at pushing fuel than
sucking it, and fuel vapourizes at a lower temperature when under low
pressure - so vapour lock is ALWAYS a possibility with front mounted
pumps - while almost unheard of with intank "pusher" pumps.

With fuel injection, an engine driven pump poses a problem - how do
you get fuel to the engine to start the engine, when the pump is
driven by the engine? Yes, it was done with the diaphragm pumps
running at roughly 5PSI for carbs - but with EFI it is not so simple.
Go with mechanical FI instead??

Sure - with all the serious problems that go with that setup. You
could not afford to own one - particularly if it had to meet emission
standards.

I have worked on vehicles with vacuum operated fuel pumps - firewall
mounted and gravity feeding to the carb, engine driven mechanical
pumps, frame mounted electric pumps, both rotary centrigugal, rotary
vane, rotary "roller cell" and plunger/diaphragm motor driven (AC) and
solenoid driven (SU), and i n-tank electric pumps, both centrifugal
and roller element and vane types.

By FAR the most trouble free have been the in-tank roller element and
vane pumps. I have seen MANY of them go over 300,000 miles without a
single problem. I have seen them last 20 years without a problem.

Up here in the salt belt a frame mounted pump of any description is
doing well to last 10 years or 90,000 miles.

Engine driven diaphragm pumps - even with the old leaded gasoline, did
good to go 10 years. 5 was a lot more common. With today's ethanol
blended  and oxygenated fuels they would not last much more than half
as long..

I have yet to hear of a vehicle fire caused by an intank pump.

I have seen several fires caused by half-wits spilling gasoline while
attempting to remove or drain a fuel tank - with or without intank
pump, and either lighting a torch to snip off a stubborn tank strap
bolt, or thoughlessly lighting up a smoke a few feet away. Or dropping
an incandescent trouble light, or spilling gas on one.

Ive seen fires caused by gasoline vapour, spilling over the top of an
open pail of gasoline and settling in the open drain of the shop,
being ignited by a chance spark from either welding, cutting,
grinding, dropping a tool, a dropped match or cig butt, etc.

I've seen fires caused by short circuits while working on a vehicle
electrical system without disconnecting the battery ground - and even
from some dim-wit trying to remove the battery power lead instead of
the ground, and shorting the power to ground, blowing up the battery.

But NEVER from an intank fuel pump failure.

And I've been in the business a long time - and worked on vehicles
from the early twenties to the 2000s.