As what Jack has said, ^^^^ sounds like the beginning of PAS pump failure.
Low mileage pre-owned pumps are in stock depending on what model of 350 you have.
Just drop me a PM if I can help further.
Low mileage preowned fully guaranteed steering racks are in stock at the moment for HR 350Z.
Just drop me a PM if I can help further.
Shipping same/next day.
Alex.
The biggest part of this job is the bleeding, so if a DE, I would recommend swapping out the fluid, line and slave in one swoop.
The whole kit comes in at circa £100.00