The Polaris 280 has a couple of issues that affect its motion and balance.
Look at the backside and note the thrust jet. It can be adjusted to push up, down or right, left. refer to the manual. Also the position of float head which can be rotated (clockwise/counter clockwise) to have the unit sit upright. The next item is the position of the float closest to the backup valve. Basically you have to look at all 3 of these items to ensure the cleaner sits upright with all 3 wheels on the pool surface. Sometimes they can become loose or someone accidently turns one of them or moves the float.
With regard to rotation it is either the pump, tires or the gearing. Check the pump that it is not clogged with anything to ensure that is giving its maximum output. if the cleaner was working fine and it suddenly stops then that could be pump. However, if the pump is clear then it is most likely wear and tear on the cleaner moveable parts. The idler wheel and the tires are normally what wears out first and can affect rotation The idler wheel mates with the rubber tires. When was the last time those were inspected? If the tires are guey then for sure change them. Also, if the idler wheel is smooth (no treads on the wheel) then that needs to be changed.
The gearing is the other part that can wear out. There are several main parts such as the turbine and the mating bearings and how it fits into the wheels which have mating gear teeth. If any of the gears become worn or part of the gear teeth break then there will be reduced rotation to power the cleaner.
You can selectively try to fix each part such as tires and idler wheel after you ensure that the pump is working at full potential. Alternatively you can purchase a full repair kit which addresses all the replaceable items noted above. See my
thread here. On Nov 2 #55. I felt it was more cost effective to rebuild my cleaner than to purchase a newer model or move to robot. That is my personal preference.
Hope this helps. Have attached manual for your reference.