So I have a 2007 Volvo 670 and the steering would get tough .I took it to 2 shops neither thought it was the gear box or the steering shaft. They both thought it was the pump so I changed my king pins and my pump and serviced the bottle it was good for 2 days and now the steering is tough again it goes in and out. They checked my drive line and changed a u joint before the pump any ideas.