My steering wheel is hard to turn at low speeds no leaks or fluid missing looks full I changed the valve that goes on the rack but still hard to turn I’m thinking it might be the pump

 

Sometimes this is related to electronic issue like when speed sensors have an issue on your wheels then steering pump is not activated and will not generate pressure. You will have only mechanical steer without any pump assist.

You need a MB diagnostics tool to check for codes.

 

I have the same problem. I thoroughly tested the proportioning valve, wiring and signal from esp module. all normal.

replaced ps pump and fluid which yielded a , minor improvement, but still harder steering than i always remember.

i will try new solenoid valve to rule it out, but not sure where to go after that other than rack itself.

appreciate anything you found out.

Mike