Hello

I have several of these newer model liner trackers(3300, 4500, 5005...) with problem with platters center axis. It seems to be somehow loose. I mean that part what is in floating chassis, and flywheel sits on it. Is it normal, does not feel normal? Has anyone else problem like this, and if,  what you have done to it?  Can it be tighten somehow?

Not sure quite what you mean. The sub chassis is definitely mobile - it is suspended on 3 leaf springs so will move up and down but also has some lateral flexibility. The bearing should be stable thopugh. Engage the transit screws and you will lock the suspension. If there is still looseness, this is abnormal.

A common problem with no real cure.

Can sometimes be improved by turning the centre bearing in it's mounting in the sprung chassis. Not guaranteed to work and a proper engineered solution is required.

I have, in the past, sacrificed a low value cosmetically challenged deck with a good bearing by transplanting it's sprung chassis into a high value deck with a loose bearing. Akin to a heart transplant!