First of all - why did you replace the pump.
The first thing I would do, assuming that the system is full of fluid, is lift the front of the tractor off the ground and get it on jack stands for safety reasons. Start the tractor and move the steering left to right going full lock left to full lock right 7 or 8 times and holding it for 2-3 seconds at lock before moving it back the other way. Lower the tractor and see what it does now that the air is out of the system.
If that does not do it, then I would check for a bypassing cylinder.
With the tractor on the ground, engine and oil at normal operating temperature, running at a slightly increased idle.
Have someone you trust turn the wheel full lock left and hold.
While its full left. Safely put your hand on both steering cylinders. If one of the cylinders start to warm up to the touch, that steering cylinder is bypassing and needs to be rebuilt or replaced.
Do the same with the wheel turned full right as well. It may take numerous tries left and right to get it to start warming up. Both cylinders should be the same temp if operating correctly. If you feel the slightest difference to the touch that will be your problem cylinder.
try that and let me know.
