Brere

Obtained one used backplate from Rimmer Bros today. In excellent condition and no sign of groove so confirms , as concluded, its wear not an original feature.

Thanks for all the helpful advice. I’m going to fill with weld and hopefully grind smooth. Will post finished version when done.

I've looked for images of new backplates but can't find any. I have checked the parts catalogues and service manual but the diagrams don't help. I decided to take both backplates off as my hub puller had sat on the shelf for 10 years unused. Both backplates are similarly affected. One worse than the other. Before taking them off I did experiment by moving the cylinder and they did catch in the depression. I am tempted now they are off to fill with weld and flatten but that could potentially leave them without a design feature. No one stocks NOS backplates only used so have nothing to compare them with. Bit of a dilemma!

Thanks didn't fancy trying to source a new backplate. Will do as advised.

A hard brake pedal on my spitfire 1500 led me to find my rear brakes were binding. Decided to service brakes and change hoses. When stripped down I could see wear on the backplate where the handbrake lever has worn at the pivot. Is this normal? I have looked at a few used backplate a on line and they have similar but not so visible wear. Would this effect the wheel cylinder sliding?