I have Geyser Kitchen Bar Sink/ Spray Faucet and it leaks at the turning joint.

make this steps and fix it. God bless you
f a faucet leaks, replace seals and gaskets . If a shower head leaks, create a better seal or replace seals .
If a sillcock wears out, replace the washers .
If a compression faucet drips from the spout, replace the washer and/or the seat .
If a faucet leaks from the handle, replace O-ring(s), replace the packing washer, tighten the packing nut, or replace worn packing, depending on the valve type.
If a ball or cartridge faucet leaks from the collar, replace worn O-rings .
If a disk faucet leaks around the base or has reduced flow, replace cracked or pitted disk assembly or worn inlet seals
If there is water under the sink, tighten the faucet-set locknuts under the sink. You also can replace putty or a gasket, replace a worn faucet, or replace leaky supply tubes .
If the aerator leaks around the edge, replace the washer in the aerator
If the spray hose leaks or has reduced flow, replace the O-ring on the diverter valve, replace a worn washer at the base of the spray head, or clean the diverter valve and spray head

make this steps and fix it. God bless you
f a faucet leaks, replace seals and gaskets . If a shower head leaks, create a better seal or replace seals
If a sillcock wears out, replace the washers
If a compression faucet drips from the spout, replace the washer and/or the seat
If a faucet leaks from the handle, replace O-ring(s), replace the packing washer, tighten the packing nut, or replace worn packing, depending on the valve type
If a ball or cartridge faucet leaks from the collar, replace worn O-rings
If a disk faucet leaks around the base or has reduced flow, replace cracked or pitted disk assembly or worn inlet seals
If there is water under the sink, tighten the faucet-set locknuts under the sink. You also can replace putty or a gasket, replace a worn faucet, or replace leaky supply tubes
If the aerator leaks around the edge, replace the washer in the aerator
If the spray hose leaks or has reduced flow, replace the O-ring on the diverter valve, replace a worn washer at the base of the spray head, or clean the diverter valve and spray head

Delta comes with a limited lifetime warranty. call them to get free parts. I believe you will need to check several things. Remove the spray head from the sprayer hose, point the hose into the sink drain and turn the faucet on. If it no longer makes the banging noise, replace the spray head. You need to look for a leaking spray hose under the sink also. If the faucet is making noise, replace the ball and cam assembly under the faucet handle. One other thing that I have run into is that the shut-off valves under the sink can also go bad and cause banging and vibration.

new plumber

Remove spray head then faucet tighten connection on the spray hose

You have a bad internal o-ring or the sprayer o-ring is leaking, if you look under the sink turn it off and then turn it back on, if you see it leaking out the center shft where the water pipes go into then the faucet may have a broken pipe or loose pipe. check and tell me where it's leaking at. You can buy kits to repiar them they are inexpensive.

you can replace spray head by unscrewing underneath the sink and bringing to home depot or Loews and match to new one and reassemble

There are 2 sets of nuts and washers underneath the faucet that holds the faucet in place. loosen them and the water lines (after turning the water off) faucet lifts off from the top of the sink. Replacement the the same, just in reverse. BE SURE TO USE TEFLON TAPE OR PLUMBERS PUTTY ON THE WATER LINE THREADS TO PREVENT COSTLY LEAKS.

there is an oring in that connection that is most likey bad. turn water off and disconnect coupling to spayer. remove the black oring and match it up at your local hardware store. when installin it lubricate it with vaseline for ease of insatlltion and to help protect it during installation.

Your problem is a simple one.

1. Turn off water to faucet.
2. Place a towel(s) in the base of the sink(s) to prevent any parts from going down drain.
   
3. Remove the handle to the faucet. (single handle only)
   
4. If not a single handle then remove spout from faucet.
5. If a single handle remove cap carefully and any loose parts.
6. Gently turn spout side to side while lifting to remove.
7. You will see a hole with a very small valve where the water comes out to the spout on the base of the faucet.

1. Remove this valve (which is a backflow preventer) and replace.
2. Reassemble and test.
   

Problem solved.