Hi all. I'm trying to replace a sink faucet and I found that the water shutoff under it doesn't fully shut off the water. It's probably possible to replace the sink as it's a trickle but just in case I run into difficulties I don't want to be stuck replacing pots under there or have to shut the entire house's water off. When I try to search online everything seems to be about the shutoff valve itself leaking rather than just not closing. I've tried tightening the knob (obviously) as well as the nut which seems to be tight.
I'm sure this isn't rocket science but can anyone tell me or point me to instructions on how to fix this up I'd appreciate. Here's a photo of the fixture:
I'm sure this isn't rocket science but can anyone tell me or point me to instructions on how to fix this up I'd appreciate. Here's a photo of the fixture: