Right, I am pleased to report that I now have a steering rack with NO play. I started to try and adjust the ball joint on the end of the rack by changing the shim washer as advised but I could not move it. The whole joint unscrewed from the main part of the rack, and even placing it (carefully) in a vice and applying a lot of force I still could not shift it. So..... I had a spare rack that I removed from another car a couple of months ago because the gearing appeared to be very rough (despite it be reconditioned only a few years previous), but there was no play in the end joints. I decided that it would be more fruitful to swap the ends over.......After a few mins of organ donation my steering rack was as good as new.
The more alarming thing was that the rack I used for the organ donation was purchased as a recon from a well known company (about 3 years ago) and when I took it apart none of the locking tabs had been bent over and some were even missing!! So there was not a lot stopping the whole lot coming undone
Thanks for all the replies, I have taken apart just about every part of a minor except the steering rack up till now but it was all quit straight forward, don't know what I was fussing about
