+1 on weak flexibles. Also full clean and lub on caliper pistons, slides, pins and mounts. Handbrake adjustment is through any of the rear wheel bolt holes, although I would suggest removing one side first. This will let you see the parts and how they interact, if the shoes are too worn and genrally make a decision on how much of a service is required. If it looks good when you check the first side (I doubt it) the you need only adjust the second side as you have a picture in your minds eye of what is going on.
Good - Fast - Cheap: Pick any two.
E23 735i; E32 735iL (X 2 - 1 Alpine White and 1 Glacier Blue); E34 535i; E38 735iL; R50 Cooper; R55 Cooper Clubman.
E21 318i; E30 318i; E32 735iL; E34 535i; E38 730iL; E53 4.4i