MFA DC Motor wobble

[chaosbc]

Hello,
I have something about my diy lathe that I am really concerned about.
So concerned that I tear it down once again to do everything from scratch in order to improve it.
Well the issue is the shaft of my MFA DC Motor (with motoreductor) wobbles and it kind of ruins the stability of the linear movement.
I desperatly try to fix this but I wondered if this is "normal" or if I would better considers in buying a better one...
Thanks in advance for your answers !