mf 165 power steering squeal

Steering more easily one way is normally down to wear in the linkage. Have an assistant turn the wheel back and forth and check for wear however small in the main shaft in the casting, ball joints, the ram rod where it is anchored in the casting, the back end of the ram and the arm which sits on the main shaft.
In the top arm you will see a large nut with a straight slot screw in it. To have movement between this arm and the one below is correct.
Adjustment may improve things. On top of the ram you will see an adjustable barrel. Remove the pins and free the ends. Slacken the big nut and screw the screw down until it goes tight and all movement is gone. Refit the barrel so that you can just fit the pins. Undo the screw SEVEN turns. This is the initial adjustment. Test the steering and unscrew or tighten the screw half a turn at a time until you find the best PAS position. If you have a lot of play in the system you will never get good PAS.
DavidP, South Wales