Originally Posted by
Oaxaca
If you are unable to check your bags through, there is a luggage storage facility (paid) in JFK Terminal 4 Arrivals landside, you could take the Airtrain round from T8, store your bags and then pick them up on the way back to T7 from the city in the evening.
http://www.jfkiat.com/information.html#
There's one at T8 too, I've used it when I didn't want to take all my luggage on part of a TP run