Brake Accumulator Sphere & Seal. If your brake warning lights are coming on, especially after you have used the brakes then low pressure in your accumulator spheres is the most likely cause...

This is the low pressure return hose for the rear brake accumulator sphere.  Looking for the front hose, search part# GMF1299 1980-1998 From Vin 50001

This is the Rear Brake Hose Pump Feed Hose. 1987-1998  Silver Spirit, Silver Spur, Mulsanne, Turbo R Pre Arnage (From VIN 20000 onward)