There is no flex on mine. I can't even see how there could be. This one?
http://devestechnet.com/Images/Restorations/1950B/D50b00028lg.jpgMine doesn't budge. It's made out of 1/4" steel and bolted securely to the original chassis bracket. I didn't go with the booster either.
Maybe the shaft is bottoming out inside the cylinder and you are putting too much pressure on the assembly. Once correctly adjusted, there is no movement. That was one of the things that sold me on the system.
