Hi all, well I dissmantled a lever to get some sizes, the washer itself measures in metric 10.00mm ODx 6.35mm IDx 0.70mm thick, convert to imperial one should get away with a washer 3/8"OD x 1/4"ID by what ever thicknes you can get, I would think by what I know that one could use a thinwall spring washer and hopefully it will come in at 3/8" OD, no bigger as the difference between the 2 sizes is only 0.008" or 0.20mm, hope this helps someone out there......regards wayne davidson Invers NZ, cold and wet at the moment, in fact all day..........