Urethane the same stuff that holds your windshield in it's about 10 buck for a tube
yup thats exactly what I wound up doing; after masking the snot out of the w/s and the body around the track, sandblasting the gap between the glass' edge and the rest of the channel, I found 2 areas of pinholes along the w/s channel both about 1-1/2" long both in the "vertical" leg of the channel in diagonal opposite areas from each other; the "shelf" the glass sits on looked fine. no holes there. So I POR 15'd the He11 out of the now bare metal, (2 heavy coats let that dry overnite) re masked everything again and filled the w/s channel with urethane, took 2 tubes to do the whole job...
3 hours to mask everything/protect glass, 20 min to blast, another hour to unmask and dab the POR 15 in,
then the next day 2 trips to town for urethane (I didnt think it would take "that" much) re masked the w/s channel to apply the urethane and it should be good! So much for the "$700-2K" estimate I got.... I have about 4-1/2 hours (my labor on myown vehicle cost $0) and with tape, the couple paint brushes I trashed, the POR 15, and all I'd guess it cost me $55 to fix;
the blasting killed the rust; the POR and the urethane will prevent any moisture from ever gettin in that track again mandating the water goes OVER instead of into the w/s track, and the wife's happy cuz she has her XJ back.... coool. just in time for 2 seperate 6" snowstorms to hit.....