To repair a Delta faucet, you need a flat head screwdriver and an adjustable wrench. This type of faucet features a small ball that controls the flow of water and a seal. This seal usually breaks down after a period of time and needs to be replaced.
Look under the sink to locate the shut-off valve. Turn the valve off and drain the sink faucet. Use a flat head screwdriver to remove the holding screw. Next, remove the handle from the faucet assembly.
Around the faucet valve, there is a bonnet nut. Remove it with an adjustable wrench. Now you have access to the rubber seals. Pull off the plastic on top of the seals. If necessary, use a screwdriver to remove the springs from the lower seal. Check the Delta repair pack for replacement seals or buy them from a Delta faucet shop.
On top of the seal, put the metal ball and cover it with a white plastic cam. Use a wrench to reattach the bonnet nut, and replace the handle. Make sure you place it in the off position. The last step is testing the Delta faucet. To do this, turn on the water and the shut-off valve.