Frank, I had the same problem on my ‘48 passenger side and subsequently rebuilt both regulators. The big external clock spring, as you found, is not the problem. There is another internal spring which you will find is broken (the small tab on the end of the spring). My first picture shows the reassembled regulator but note I’ve rebuilt it with the housing held together with nyloc lock nuts. You are going to have to get creative (wear safety glasses) and drill out the original rivets holding the housing together to gain access to the real internal problem. The next picture shows the replacement internal spring. Classic Parts, (1947-54) Window Regulator Spring Item Number 18-781. $3.95 each Good Luck. Dave
