What was found
PART NR M-3485 HAS A STEEL BEARING PRESSED INTO AN ALUMINUM BEARING CAP. IT PROVIDES SUPPORT TO THE ROTOR. DURING ROUTINE 500-HOUR INSPECTION (500 TTSN), A BLACK POWDER-LIKE SUBSTANCE WAS SEEN THROUGHOUT THE MAG. FOUND STEEL BEARING WAS MOVING INSIDE THE BEARING CAP, ABRADING ALUMINUM PARTICLES AWAY TO CONTAMINATE THE MAG. SUSPECT EXCESSIVE CLEARANCE AT OPERATING TEMP. SUBMITTER RECOMMENDS: 1) TIGHTER PRESS FIT BETWEEN BEARING AND CAP, OR, 2) FLUSH SET SCREWS AROUND EXTERIOR SIDES OF CAP TO HOLD BEARING IN PLACE, OR, 3) MAKE ALUMINUM CAP OF STEEL TO AVOID DIFFERENT EXPANSION RATES.