Fuel pump problem on 1992 Ford F-250

My fuel pumps I keep putting in my truck in the rear tank are going bad. I have tried motorcraft and airtex fuel pumps, but same problem. Any idea why these pumps are going bad?

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4 answers
Check your wiring harnesses also. They are known for issues, and even had a TSB for harness pigtail replacement on similar models. Look for damaged connectors and corroded terminals.
dirt and debris are the most common reasons for failure. remove the tank and have it completely cleaned out.

Roy
Are you sure the pumps are bad? If not you might try powering one up out of the truck. Some times fuel pump relays heat up and work intermittantly.
All the other answers are correct, you may want to check there is a black piece of plastic that is bad for coming off. It will cause your truck stop running when you have less than a quarter of a tank of fuel. Good luck.