Sector gear bearing issues

Hey guys. Im having problems with my nylon gen 8 gearbox. The bearing on the left side for my sector gear keeps popping out after just acouple shots. Its rinning a chi hai red, generic 18:1 metal gears and a 1.2 spring. Shimmed it to @LowGuido youtube shimming video and its all sweet and not loose but spins free. Also i did notic that the sector gear is not center with the plunger rack but still a full mesh on the gears… even with no shims or anything theres nothing i can do to align the sector gear straight to the rack. What can i do? Just get a metal gearbox?

Also on a 11.1 volt but even a 7 does the same thing?

I can only imagine that if the bearing is popping out that there isnt enough shims. Did you check the shimming with only the sector gear in the box?
Also the sector gear only ever really engages half the rack due the the physical position of the gear.

Ok so the offset on the septor gear is normal. As for shiming i followed your video. Shimed it each seperate gear so therez only the slightest movement but its still spins free. After the first time i stuck a 0.2 shim on the side it popped which basically gave it a small bit of drag but didnt side shift in the case. Its happened 3 times and i think the scoring in the bearing hole on the left hand shell has elongated. I think i probably got a dud box so ill go straight to a metal box. Can the red chi hai motor be too much power for the nylon @LowGuido ?

If the box is damaged then you will need a new box.

Thanks man. Will be getting a new one this friday