How do I remove the "U" shaped brass ring under the sink on a Grohe kitchen faucet?

Most Grohe faucets loosen from the TOP! Here, pull out the spray and the spray hose (pull off or loosen from under sink) and then pull up on the spout to remove the spout. Once the spout is up and out you can use a crescent wrench to grab the flat faces of the inner valve body and start to spin it counterclockwise. It takes awhile, but eventually the U-shaped nut will fall off.

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Mark