Power steering box

Hi folks,
Going to remove and overhaul my power steering box, tight going one way and sloppy in centre position. I've adjusted it before but feels worn.. Does anyone know where i can buy internal parts from ie bushes and bearings if required..
Cheers Steve

I was going to do the one in my previous discovery but had trouble trying to find an overhaul manual at the time so went with getting a recon one

if it has bearings and they are broken then the will have marked shaft rendering unit scrap ,early ones had 3 bushes on sector shaft later 3 needle bearings that can be bought from bearing suppliers ,bushes are available from britpart etc,seal kit stc2847 is usual thing that can be fitted while keeping unit cost effective,input shaft has 2 ball bearing races and if worn unit is scrap as inner race is part of input shaft ,the race nearest the uj for linkage has shims behind it the shims determine tight spot of box is in the center and are selected as such,before removing top cap undo rack adjuster screw on side of box locked with imperial allen screw ,and remove thrust pad ,if you want i casn tell you exactly how to reset box