Kelsey Hayes Brake Caliper Washers

For you guys with brake experience, I'm finally ditchig the 50 year old drum brakes for some disks using the 4 piston Kelsey Hayes style calipers. The only thing I seem to be missing is the seal or crush washer that is installed between the caliper and flexible brake line. Anyone know where I can source the right washers for this?

I was able to find the correct copper washers at my local O'rielys in the help section. I was expecting to need some type of crush washer but apparrently just a plain copper washer is enough to make a good seal.