780 V6-2849cc 2.8L SOHC B280F (1987)
Vacuum Brake Booster Check Valve: Service and Repair
Non-Return Valve In Hose, Replacement
Non-return valve in brake servo/intake manifold hose, replacement
Y1. Pull off hoses
Y2. Install new non-return valve.
Note: White side of valve should face servo.