Hapco Heavy Duty Power Steering Fluid provides for a smooth operating power steering unit and is compatible with all other power steering fluids. It contains special anti-rust and anti-wear lubricants that are resistant at all operating temperatures. It also maintains its viscosity over a long period of time and will help prevent rusting and corrosion. Guaranteed to help extend fluid life and help prevent wear. Always be sure to change fluid regularly, as manufacturer suggests. For steering stiffness, use Hapco Rack and Pinion Formula.