ur-q rear brakes...

[PHBJohns at aol.com]

Can anyone please confirm the size of Allen key I should be using to remove 
the rear callipers on my 1983 ur-q? 10mm is definitely too big and 8mm seems 
a sloppy fit. I do not posses a 9mm key and this seems an odd size...
I also need to replace the rear disks and are considering going for new 
grooved disks. the fronts are standard and do not need replacing. Will this 
upset the brake balance?

Thanks in anticipation,

Paul Johns
'83 ur-q
'74 80 GT