Fuel flow was erratic, with a slight fuel leak from pump drains. Inspection revealed debris in servo screens. Teardown report showed drive couplings pitted, blades and liners scored, rotors worn. Debris in servo filter appeared to be pieces of the liner. Replaced both pumps. (The same engine-driven fuel pumps (p/n 200F5002) were installed new at engine overhaul. They were replaced at 372 hours and 389.7 hours. The pumps removed had 776.3 and 794.0 hours.