Knock When Steering To Left

[leeds2592]

Hi,
When driving and I steer to the left about half way between full lock and half lock I get a sort of knock sound and then it sounds like something is grinding/rubbing on something.
It only happens when turning left, its fine when turning right.

Anyone know what the problem could be??

Cheers

 

[maynard]

Possible driveshaft. They tend to knock when turning.