Hi
@Drover , although I have never seen wear on the brake backing plates of vans, (perhaps it is because I have not had vans long enough or not hammered them in bad conditions without checking for wear), here are some examples of backing plate wear on cars I have had experiences with. These were from cars with hydraulic drum brakes, single piston where brake maintenance was poor or non-existent! There is a definite need to reduce friction and wear between the brake shoes and the raised platforms on the backing plates. Perhaps the wear pattern is different with electric brakes???
The springs have nothing to do with keeping the shoes off the backing plate. Quite the opposite!!! They are for retraction of shoes after expansion for braking. The following is extracted from the service book for one of the vehicles:-
"Each shoe is held against the anchor by a brake shoe return spring. The shoes are held
AGAINST the backing plate by a hold down spring passing through the centre of the brake shoe and fastened to a clip in the backing plate. Each brake shoe
RESTS on three platforms in the backing plate. These platforms ensure parallel alignment of brake shoes to the drum. ...........".
I hope this clarifies the need for some high melting point grease on the surface areas where shoes are moving over the raised platforms even on vans.