PART NO.  SPL.PAGE  DESCRIPTION                                                           
17H7734   16.K.3    Caliper -R/H -(front brakes, 1600 and 1600-MK-II Std.model)
17H7735   16.K.3    Caliper -L/H -(front brakes, 1600 and 1600-MK-II Std.model)

17H7874   16.K.3    Washer -tab (4) -(caliper, front brakes, 1600 and 1600-MK-II
    std.model)

This is the 17H7874 Tab Washer used to secure the 17H7873 Bridge Bolts in the front disc brake caliper of the MGA. The Workshop Manual says do not split the caliper for service. But it also talks about what to do if it does have to be split, and replacing these bolts and tab washers is part of putting it back together. As this part has a BMC special drawing number, it is not a standard part from a local fasteners supply store. The part is also difficult or impossible to find from the normal vintage British parts suppliers. So if you need them, you may have to make your own parts.

The metal thickness measured from an original part is 0.050", so it could be made from standard 18-gauge (0.048") body sheet metal for the MGA. If you scale the picture above you may have a tracing template. This is for a 1/2" bolt,so the center hole needs to be 0.510" to 0.540" diameter (17/32" bore or drill size). It would be nice if we could get one of the traditional vintage British car parts suppliers to commission a minimal production batch for resale.