There was a similar discussion earlier on that covers the replacement pumps currently available. MB, Bosch & Nissan all OK.
1975 R107 450SL Leaking Fuel Pump Replacement - Mercedes-Benz Forum
The attached pic shows the electrical connections on a new pump (my spare). Canister of pump is crimped on, so any fix would have to be from outside. You could try, but now that replacement pumps are more reasonably priced, maybe a new one would be best choice?
But I would suggest first making sure that that is where the leak is.
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Graham
85 300D
,72 350SL, 98 E320, Outback 2.5