Power steering is hard when the car is still then easens once I step on the accelerator. I have replaced the power steering pump and once the engine is running once can see the steering fluid circulating when you open the cap on the power steering reservoir. About two months ago I also replace the steering box. The car is pretty old so I get parts are getting to the end of their useful life, but at the same time its frustrating as it now has a new steering pump and steering box. The pipes have also been replaced. Will really appreciate your input on this.
My car has a manual transmission.
Well given the symptoms, it sounds like the power steering pump is not putting out adequate pressure. When you replaced the power steering pump, did you use an OEM pump? If not, I would suggest having the power steering pressure checked, and replace the pump with an OEM pump if necessary to ensure the pump is good quality. Also, I know you said the pipes have been replaced, but does that include the pressure hose between the pump and the steering box? If not, that could be an issue as well.
You should also check the front end steering and suspension components, as a failing steering rod or ball joint could be binding, causing the steering to be stiff until it has enough pressure to overcome the bind.
If you want to have the steering problem thoroughly diagnosed, you can contact a qualified professional, such as one from YourMechanic.