So I had to re-think the tank design a bit. The lower drive section is fine, although I had a problem. When putting the tank through its paces over very rough ground one of the brackets holding one of the motors broke. All that happened was one track went slack but luckily did not come off. The brackets holding the motors have now been given a significant upgrade so that will not happen again.
Main probelm with the tank was the turret. The drive and lower section worked well and did not have any real issues. The turret on the other hand had some terminal problems.
The first was the bouncing of the turret. This was not due to the bearing as I thoguht but the whole base plate on the turret. The turret was made from recycled metal and the metal used for the base of the turret was no good. The steel was deforming to easily and causing the bouncing, a bit like a spring. Due to the fact that the base was moving so much the drive gear to the turret was moving to much and after a heavy day of ofroad driving the gear system was shot. To make matters worse the turret design was also causing problems with the gun elavation.
Anyway life would not be fun without problems.
After some thought I decided to scrap the old turret design and come up with something new.