Washer sizes (internal dia x external dia x depth)...

Sump drain bolt: 14mm x 16mm x 1.5mm (aluminium)

Tank (frame) drain bolt: 8mm x 14mm x 2mm (copper)

Air bleed bolt (top of filter housing): 5mm x 9mm x 1mm (copper)

TIP: Get yourself half a dozen of each when you buy them so you've always got a ready supply; they only cost a matter of pence.

__________________