Series 3 Front Brake Problem

Do restorations ever get finished?
This project has been going for several years but there is always another little matter to deal with.
S3 standard single leading shoe front brakes. I've replaced wheel cylinders, linings and drums. One original drum was perfect but the other was fairly heavily scored for no obvious reason. I have now discovered that the trailing shoe seems not to pull off the drum to the extent that in reverse it tends to lock up. The lower spring (part number 218913) looks perfect but I have ordered a new one just in case. It is difficult to see why this should cause scoring of the drum though. I would be grateful to hear any thoughts on this niggling little problem.

Spring may well be your problem, check slave piston retracts with ease although should be good as replaced.

Also, check the shoes faces are parallel to the drum surface. Mine were mis aligned and caused one shoe to wear more than the other and uneven wear across the show surface.

Co!

Is the top of the trailing shoe chamfered if not it will grab the drum in reverse and make brake bind.
As you normally only do low speed in reverse a chamfer is not an issue to breaking efficiency.
Try putting some chalk across lining and along edges of lining outer edge fit drum and rotate hub if all chalk marks around edge disappear maybe worth trimming edge of lining also.

Thanks for the very constructive replies.
It may well be the spring and that will be the first thing to check when it arrives. It would only need to be a couple of millimetres shorter to make the difference.
Again, thanks
J

Its one of the reasons i swapped for disc brakes, yes a lot of money but no issues

New spring arrived £1.69 delivered from eBay seller.
Slightly shorter as hoped and the trailing edge clicked into the cylinder much more positively. A bit of jumping to conclusions though. The vehicle isn't on the road and it seems that all the wheels are dragging slightly
I guess that a bit of running in will help....eventually.