and also for yours, Converting a corsa B rear beam to discs.
First you get your donor beam,
This came from the k reg cavy sri I got my 2.0 16v from then you unbolt the hubs,
that lets you get at the spacer plate that is welded to the beam and has the holes with the with the hub to fit, carefully grind off the beads of weld from each side of the plate
(arrowed) try not to cut into the plates as you need them,
Then you get your corsa beam and you unbolt the drum hub and remove the spacer plates from the beam taking care not to grind into the beam this time ,chuck the small corsa plates and offer up the cavy plates you will see the difference right away,clamp the plate onto the beam , set it so that the plate is level with the top edge of the beam and the hole in the middle centred ,you have to be very accurate to get both sides the same as this affects where the wheels will sit in your arches but dont worry too much as theres not a lot of room on the beam surface so you can't go far wrong then weld the plates onto the beam.The hubs bolt through this plate so the welding does'nt have to be ship building standard just a zip up each side.
Then drill out the beam at the cavy spacings in the plate just welded on and opened out the centre hole to suit the abs type hub that later cavys and astras have, early mk2 gtes dont have the lump sticking out the back so will just bolt straight on (they also have bolts through the hub not studs and nuts like the cavy)
then bolt on the hub the top 2 nuts will need a bit of relieving cos they are very close to the edge of the beam now
f**k! see the like pole thing running round back mines in the middel of the beam ( ps idc if i used the wrong word BEAM is the word im using 
) :L
