Steering hydraulic pump

Good day team,

My car was fixed by replacing the ABS sensor and wheel bearing. Thank you for your help.
I am facing another issue, soon after replacing the said parts, the car was running smoothly and suddenly the steering became stiff, and mechanics said that the hydraulic steering pump was defective. The problem persists after replacing it and we divided it into two parts by the steering rack which arrived 3 days ago. The steering is back to being smooth as used to be, but hydraulic pipes are getting hot which I think is not normal.

Question:
What's an allowable temperature should be on steering hydraulic pipes and pump?
Please assist me with that with consideration that the steering doesn't have a sensor on it.

Thanks,

Muhimu