Fixing leaky Delta faucet - what am I doing wrong?

Question

I've got a leaky bathroom sink with a Delta 2-handle faucet that I'm unable to permanently fix. Every time I replace the seats and springs, the problem goes away for a day or two, but then returns. Every time I pull out the cartridges to replace the seats, I find the old seats are nicked at the top (see photo).

I've gone through this routine five times in the past few weeks, so I'm presumably doing something that's causing the seat to be damaged after some use. Anyone have any idea why?

Answer 1

Looks, and sounds like, the actual metal part of the valve seat is probably messed up from over tightening. It could possibly be fixed with a grinding stone that is fine grit and the same diameter, to reface the metal. But be careful to not take too much off or the seals won't seat properly. You might also look at the warranty that came with the faucet. It could have a lifetime warranty and be as easy as getting a replacement.