I use this cap to pressure bleed and change my brake fluid. It was originally suggested by another member here. Perfect fit on factory brake fluid reservoir.

"Power Probe BA10 Small Adapter for Toyota is a small adapter that fits Toyota and Lexus master cylinders with diameters of 1.65–1.83 inches. It features an expandable O-ring for a leak-free seal, 3 tab cam locks, and a 360 degree swivel automotive style air hose nipple. The BA10 is also color coded red to identify it as a Toyota brake adapter""

 

At least it was easy swap to get the new caliper on and bled.