This is one that's been going on for ages but I haven't worked it out. when my steering is at full lock I get squealing from some part of my PS system. I thought i'd cracked it when I changed my v belt tensioner and belt during the summer but it's still the same. it's worst when i've just started up from cold, suggesting the pump itself or belt are less forgiving when cold. At times I get a bit of squeal just turning half way, not even on full lock. that does tend to be when the car is cold though.
any ideas anyone? And no, it's not a cat stuck in my undertray