I have just changed the torsion bars in my axle as the were only 19mm, I seen in one of the guides you need to set the gap to 0.05mm? Can someone give me a idiots guide to doing that, I know you use the double ended threaded bit with the cut for a screwdriver, do I hold it and tighten the 13mm nut ?? Does that pull the trailing arms onto the tube?? Where do I measure 0.05mm ??