when i push it down it stops leaking and when i let go. it springs up and starts leaking. does anyone know what that connector thing is??ty can i replace this with something else to stop the leak? i have no idea what it is called.
This thing you describe may be the shutoff valve. If so, it has a handle that you can turn to shut off the water to the kitchen faucet. There are two of them: one for hot water and one for cold. There is a nut under the handle that may have come loose. Get an adjustable wrench and try turning the nut clockwise. You'll want to tighten the nut until the leak stops, but not so tight that you can't turn the handle. In the event that you are not able to get the leak to stop, you may have to replace the shutoff valve. Turn off the water where it enters the house, then remove the shutoff valve from the copper pipe using two wrenches: one to hold the valve still and one to turn the nut that is over the copper pipe. Take the valve in to Home Depot or Lowe's and get a replacement, taking care that the inlet and outlet pipe sizes and threads match the old valve. Install the replacement and turn on the water.
Sounds like maybe it is a compression fitting. Is it a copper pipe that looks like it goes though a nut? If so, try tightening the nut with a wrench. Do not overtighten, just give it a little turn (clockwise), hopefully that will stop the leak.
I have made a lot of sink repairs and cannot imagine what you are dealing with, sorry
