How do I disassmble a jado kitchen faucet with

William, you or a plumber will have to replace the cartridge and seals to stop the leaks. The parts may have life time warranty, check your manual if you still have it. Check the attached links,instruction and guides, Good luck
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KOHLER Canada Warranty Information Planning
Maintenance Replacement Parts KOHLER
Fort single control pullout kitchen sink faucet with color matched...
Kohler kitchen faucet repair

take the old one to home depot and have them find a replacement

The specs say that there are two check valves but the diagram does not show them. Take the weight off the hose and see if it is causing the restriction. If it is not, what is the water pressure in the house? The 2.2 GPM is the maximum flow rate.

Having the same problem and just found the spec sheet. Going to try to repair today. Hope this helps!
http://www.us.kohler.com/onlinecatalog/pdf/1013943_4.pdf

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.

By "leak in the stem" I assume you mean you're getting water in the cabinet below the faucet. High likelihood is it's the hose - either loose where it connects to the faucet or the sprayer. You can pull it out and check to be sure it's tight at the sprayer. To check the faucet end, you'll need to be under the cabinet with a light. If you don't find one of those connections loose, it's likely one or the other is leaking, due to a hose defect or washer (or missing washer).
The only way to see that is to turn the faucet on full (cold) with the sprayer pulled out and look for a leak in the hose behind the sprayer. If not there, leave the water running (may need another person to hold the sprayer) and inspect under the cabinet with your light for a leak either in the hose or at the connection to the faucet. If the problem is the hose or one of the nuts, it's an easy deal to buy a replacement hose - Home Depot stocks Moen.

most of these sprayers have a compression fitting
for attaching if it gets bent or twisted you must
replace with new fittings or new sprayer

most of the the pullout sprayers need a rubber washer were it meets the hose chek for cracks and replace.

ouch sadly im sure it was pricy to have him out  so my suggestion would be to call him back and have him take off the price of what he charged you or have him fix it for no charge could be just need some plumbers putty around the faucet to stop a little water that may seep threw under the faucet good luck 

Many new faucets require some assembly before mounting to the sink; if that is the case, follow the manufacturer's directions. With most pullout sprayer faucets, the sprayer needs to be threaded through the faucet body first. Insert the rubber gasket between the base plate of the faucet and the sink top to create a watertight seal. If no gasket is provided, pack the cavity of the faucet with plumber's putty, then insert the faucet body through the holes in the sink top. Thread the mounting nuts provided onto the faucet shafts, then center the threaded shafts in the sink's holes and tighten the nuts firmly. Many manufacturers include a special long socket specifically to aid in tightening the mounting nuts. A hole in the socket accepts the shank of a screwdriver, guiding it as you tighten the nuts. If you're mounting the faucet on an installed sink, use this method. If you're installing a pullout sprayer faucet--or a faucet with a separate sprayer--now is the time to connect the sprayer to the faucet body. Check the manufacturer's directions to see if using pipe-wrap tape for this connection is recommended. Use an adjustable wrench to tighten the connection. Most pullout sprayer faucets and faucets with separate sprayers come with a counterweight that attaches to the sprayer hose. This weight helps retract the hose back in to the sink cabinet after you've used the sprayer. Follow the manufacturer's directions on where to secure the weight, and take care not to crimp the hose as you attach the weight. Hook up the faucet's hot and cold supply lines to the water supply shutoff valves under the sink. If necessary, gently bend the copper tubes coming out of the faucet for better access and connect flexible supply tubes to them. Simply wrap a couple of turns of pipe-wrap tape around the threaded nipples on the valves and connect the tubes. Tighten the nuts with an adjustable wrench.