Gemmer steering leak

Have a 1990, 90 with a leaking Gemmer six bolt steering box...

what's the information on fix
have read on net... arm difficult to remove, new seals leak when fitted, OEM seal kit £157 also leaks, get Claron and Eriks seals/orings
or change to four bolt with a different cranked arm

what's the guru's on here information

the manual I have doesn't even show the main shaft only details of the input shaft

any re con's out there as MOT at end of month looming


thanks bustersbus as I'm removing it with these instructions...
http://www.landyzone.co.uk/lz/f41/steering-box-renewal-63806.html

thanks jamesmartin
http://www.landyzone.co.uk/lz/f7/6-bolt-steering-box-177194.html

fairly straight forward ,if stripping completely ,remove 6 x bolts and adjuster lock nut and wind ajuster through top to remove top,
use one of the linkage uj to turn input shaft (also very useful for resetting )
so that sector shaft is aligned for removal ,tap sector shaft out ,undo cap on input shaft and tap shaft out
keep bearings and rasces together inner race were input shaft exits box has shims behind it these set center tight spot of steering box ,
undo rack adjuster on side of box (little imperial allen key for lock screw)remove endcap for piston by turning end cap with suitable nut
welded to bar till end of wire can be pickled up ramp in slot then wound out ,if end cap is stuck in refit sector shaft in rack in box and
use drop arm on end to knock piston against end cap to release it,if box uses needle bearings you will need to carefully grease them to hold them together,

while sector shaft is out ,change all seals,when rebuilding fit input shaft first and using uj,
tighten to remove freeplay and add a little preload but not enough to make it notchy as you turn it ,
then refit rack and piston and sector shaft it may take a couple of attemps to get teeth in the right teeth on rack ,fit top ,
fit piston end cap ,adjust top adjuster a little then turn from lock to lock and find center ,when centered fit rack adjuster
and screw in just enough to remove freeplay between rack and sector shaft ,adjust sector shaft adjuster to remove freeplay add a little preload but not too much
that its tight or notchy,turn input lock to lock and back to center check/adjust rack adjuster has no freeplay and check top adjuster so that theres no freeplay
between sector and input shaft ,check tightest spot is in the center either side of this box gains freeplay till theres a good it at each full lock