boom vang strut weak

[Jim Hardesty]

I have factory in mast roller furling main.  The Sparcraft boom vang strut (factory) just barely holds the boom up any boat movement and the boom drops to the dodger or lower.  I have been using the topping lift to keep the boom up.  Now that I bought a new mainsail with roach and battens I want to get away from using the topping lift with the sail.  Before I blindly just take it apart to see what I can do wanted to ask.  Has anyone added to or replaced the lifting spring?
Jim