Hy Lode51, if I'm reading what you wrote correctly, you put new brake linning on unturned drums. If that is the case, you may have created hard spots in the linning which will squeal. You have turned the drums, but the hards spots are still there and they're not consistant with the drum surface, try sanding the surface a bit to break the glaze on the linning. Of course there are linnings which are hard and can cause noises. Linnings must eventually wear into the shape of the drum, [consentric with the drum] and this process does take a while, as it is doing this your contact patch is relatively small and concentrated, which can glaze up that patch, and become noisy. If you take your linnings and drums to a good brake shop they can arc your linning to a more correct shape for your drums, hope that helps.
