Trailer tow vehicle fuel pumps

These electric pumps, according to an informal survey of friends and
acquaintances, fail with alarming frequency - usually within ~50K miles and
each 50K thereafter.

That's counter to my personal experience. I've done four fuel pumps
for my Volvo tow vehicles; none of them let go prior to the 200,000
mile mark. All of the replacements outlasted the vehicles.

Once you are on the roadside, you will find that no matter how
good you may be at fixing cars, there is nothing you can do but call a tow
truck since pump replacement requires a high bay hoist where the gas tank
can be removed. It just isn't a DIY job.

Disagree:

A) Everything is DIY for the resourceful and motivated.

B) All of the cars for which I've replaced the in-tank pump allowed
access through a panel in the trunk or under the cargo deck. None so
far have required dropping the tank.

C) For many cars with Bosch K-Jetronic, LH-Jetronic, and similar
systems, there are actually two pumps: an in-tank centrifugal pump and
an external constant-displacement pump. The in-tank pump just delivers
fuel to the main pump, and is critical only at 1/4 tank fuel level and
below. The usual sign of a failed or failing in-tank pump is poor
running below 1/4 tank, and whining noises from the main pump.

D) In my experience, failure of fuel pump relays is far more common
than failure of the pump. Usually they can be fixed by peeling them
open and resoldering the crack-prone joints where the heavy relay
frame meets the circuit board.