Thanks for your replies, please keep us posted Motorhead. I went to the Stealership and asked the parts guy (most helpful I might add). He said there wasn't a special tool and went and asked their brakeman. T45 or allen key says he. I went to 2 other parts stores and there is nothing between a T45 and T50 according to them.
I put the brakes back together as they were until I can find the right tool to do the job.
Richard