sloppy stearing in the scania

[cosworth34677]

ok i've had this problem for a bit but i want to fix it now. ok i put two different servos, and full ball bearing in the truck ,including the stearing but he truck wont return ti the center and drive straight. its not so bad whenim driveing at the park or around the house on the streets. but it shows up when im trying to drive down a sidewalk. everytime i readjust my path the truck will pull the the direction i just adjusted to. so going down a tight path is out of the question.

its a tamyia scania pretty stock with a brushless crawler motor, the other thing is there tons of slop in the front wheels. i know all tamiyas have little slop but im thinking that helping with the bad stearing. any help or fixes