Weird steering problem

[Rokas Reipa]

Hello everyone. Been having a weird steering problem with my car recently
and was hoping somebody could point me to a possible solution. Car is a 93
100s 5sp with servotronic disabled. When driving, it is noticeably easier to
turn the wheel to the right than the left(i.e. the level of assist when
turning to the right is noticeably higher). This lasts for about a quarter
turn and then the assist drops noticeably(almost to the point of 'jerking'
the wheel back) and it feels normal when turning it further. What can be
done to prevent this from happening? It is quite unnerving to have varying
degrees of assist when maneuvering the car at a moderate speed. I thought
this problem would go away when I disabled the servotronic but it still
remains. Please help! Thanks,

Rokas
93 100s 5sp