Does anyone converted from dry brakes to wet ones or disc?
... wet ones only has series 3321 Super up to Proxima and this are every time disc brakes.
Zetor doesn't produce wet drum brakes.
And If you mean convert from dry drum brake to dry disc brakes ... forget it directly again, believe me.
To convert from dry drum brakes (e.g., Zetor 5211) to dry disc brakes, you would need not only the internal components (drive shafts, automatic brakes, brake discs), but also the externally mounted parts (handbrake rods, wheel brake cylinders and their brackets, brake lines, etc.), but above all, the appropriate differential housing and the appropriate axle spacers between the differential housing and the portals.
That makes absolutely no sense, neither economically nor technically. Yes, dry disc brakes brake better than drum brakes, but automatic brakes tend to lock up at the slightest touch of the brake pedal when used infrequently and especially in high humidity. So, they also have their problems.
A conversion to wet disc brakes would be even more complex than the one just described.
If you really want to do that, get the entire rear of a Zetor 3321 Super to 7341 Super Turbo and convert it completely. And even then you still need new brake lines and the modified handbrake linkage.