[W126 Coupe] Buzzing Fuel Pump

[DCrawford at tompkinsinc.com]

Perhaps someone can give me advice regarding the fuel pump on my "84 500SEC.
I recently had the fuel filter replaced as a part of a routine maintenance
visit to my local MB shop.  When I got the car back I discovered the fuel
pump was now continuously humming/buzzing.  The shop said it is not uncommon
for buzzing to occur and that it was not an indicator that the pump was
beginning to fail.  At roughly $250 for the pump plus labor, I'd put up with
the noise if I were sure it was not getting ready to fail - I do not want to
get stuck somewhere in the boonies in the middle of the night.

Any opinions about what the best course would be or past experience with this
type of problem?

Thanks for all the help,
Dave D