More of a collar than a cap I think. Regardless of the name, it's a nut. If you tighten it, it will make the servo saver stiffer and less forgiving on the servo.
What setting would make it turn better under acceleration/speed. My steering goes crazy in the bumps at speed. I want it to stay steering the way i want it to not going everywhere like a crazy piece of ****.
Are you sure it's the servo saver giving way or the servo is too weak for the task?
Tightening the collar will make the servo saver "stiffer" so it won't break away so easily.
When looking down on the truck when it's on all 4 wheels, turning the saver collar counter clock wise should tighten it up.
Test it before you go and adjust it. Turn your radio on, reciever on and try to turn the tires left/right by hand and see if it's the saver that's giving or the servo.