Saab 93 Power steering

[red tasman]

Hi, has anyone changed a power Steering pump on a 150 tdi Saab 93 (06 model). Steering has started making noises and sometimes a bit stiff to steer, then it lightens up again partway through the turn. Seems like pump to me, how easy is it to replace? it looks quite accessible, anything i should watch for?
Thanks, Roger.