Originally Posted by jimc101

I have a M975 caliper with a SLX (M675 servo wave) lever, works great, used to use the same caliper with a XT (M775 non servo wave) lever, worked ok then as well. Both using the BH59 hose & gold inserts, not the newer BH90 & silver inserts

For repairing Shimano brake levers, and parts in general, they will normally sell assembles, but not specific parts like washers, you can see what is available by using the tech docs SHIMANO Dealer's Manual / User's Manual

No really seeing an issue with how Shimano do this, as others do, it limits the number of SKU's they need to stock, and normally if you have damaged part of an assembly, the rest will benefit from being replaced as well.