I took my 1987 K75C for its first run today. It ran very well but I noticed some squealing when I put the rear brake on. When I got home I removed the rear wheel and it looks like the wheel is touching the edge of the brake pads.

I assume there should be the standard BMW spacer between the wheel and the hub. Can someone confirm this please?

all bevel boxes k75 - k100  should have the spacer , im guessing the brake disk is touching the calliper body as brakes applied ,?  but could be a stuck piston internal to the calliper causing the noise ?

As the 75C has a drum brake and not a disc brake, it has the different rear wheel.  Due to the design the four wheel bolts are shorter and a spacer is not fitted.  

There is a bit in the Haynes manual about fitting a rubber damper around the rearmost return spring to prevent brake squeal.  There is a bit more detail to it than that if you need to have the damper fitted.  You may have to replace both springs as well.  

Do you have a Haynes manual for K bikes?

Check the shoes for glazing.  A light scrub on the shoes and the drum with 400 grit to break the glaze.  A very light film of spline lube on all the moving parts being very careful to keep it off the shoes and the drum.

TacKler wrote:. . . fitting a rubber damper around the rearmost return spring to prevent brake squeal.  There is a bit more detail to it than that if you need to have the damper fitted.  You may have to replace both springs as well.

The condition is described in this BMW service bulletin.

Really none of these apply. It has a drum brake and the EDGE of the shoes is touching the inner part of the wheel centre like the wheel is going too far over the hub. Actual brake shoes are ok and I did de-glaze them. I'll get a photo later to show what I mean

UPDATE:
Gaz has supplied me some info on centreing the brake shoes. I'll give this a go when I get a chance.

ANOTHER UPDATE:
Problem solved.