I had a professional company, in business for 40 years and specializing in the older stuff come out and put new seal (I had new windshield on hand because old one was de-laminating) on my '79 Power Wagon. I had removed old one myself and thoroughly cleaned channel myself. There was ZERO rust and I cleaned it to like new. First rain came and it leaked like a sieve. Worse than the decades old one. HEAVY drips from top. VERY heavy around driver's corner (maybe just runs that way). Passenger side floor very wet too, and never got wet there.

They had run some urethane sealant, lock strip seemed to fit very well, and they seemed to know what they were doing. Any tricks I should know about for when they come out and re-do this?

Thanks.