Are you absolutely sure it's the windshield that's leaking?
YJ's are notorious for leaking through the heater duct.
Thing is, it's not the heater duct that's the cause. The cowl vent, gets clogged with leaves & crap. May even find dead critters in there!
This thing has a grille with little slots, & is between the hood & windshield.
You can unscrew the little grille, & clean some of it out, but the real problem is usually the drain tube.
You can find this tube, coming out of the firewall in the engine compartment.
It's a big black rubber hose ( looks like a jeep colon) that 90's down right away, ending with a pinch just above the starter. (on a 4.2L)
Clean that out with a garden hose from inside the grille above it.