How to replace old 4 bolt power steering pump

How to remove and replace my old defender 90 4 bolt power steering pump

Good Evening,
What model and year is your 90? What engine is it fitted with?
Need info to assist.

I am sure you will find a video on YouTube which will show rather than try and explain.
If you look at the offending unit it's quite logical how it's removed.
I would fit a new drop arm aswell, saves the aggravation of trying to remove the old one.

And they are heavy! Waaaaaayyy more heavy than they look!

Are you talking about the box, mounted to the chassis, or the pump mounted to the engine?

Either way @Anaconda advice of being fairly logical when you look at is is correct.

For both you start by removing the pipe work.
For the pump, it is then remove the belts, and unbolt the pump from the engine, refitting is the reverse of removal!
For the box, remove the steering bars, and unbolt the box form the chassis refitting is the reverse of removal!

it really is as easy as that, it is just a nut and bolt job for either but access is a challenge and the parts can be heavy and awkward!