Power steering advice needed

Hi

I have a 1984 110 CSW (2.5 diesel) which i've owned for 10 months. Recently I have noticed a "dead" spot when turning the wheel (when moving only) more prominent going right, but it feels as if the power steering is failing, then starting again. There is a small leak on the power steering pump, which appears to be on the supply hose where it is itted to the pump, (not the outlet banjo bolt) which is confusing. Is the problem possibly something other than the power steering? What should I be looking out for?

cheers

Mike.

Have you got oversized tyres? this can cause what feels like a tight spot, does it happen when turning left or does it occur either direction. has there been any adjustments made to the steering box?
If it only occurs in one direction I would look at the knuckle joints.