What was found
AFTER LANDING, OIL FILTER BYPASS LIGHT ILLUMINATED ON NR 1 ENGINE ALL OTHER INDICATIONS NORMAL. ACFT GROUNDED. PARTIALLY REMOVED NR 1 OIL SCAVENGE FILTER BOWL, DURING REMOVAL BOWL THREADS SEIZED ON HOUSING, REF MM 79-21-06. COMPLETED REMOVAL OF NR 1 ENG OIL SCAVENGE FILTER ASSY AND INSTALLED REF AMM TASK 79-21-04. INSTALLED DIFFERENTIAL PRESSURE SWITCH CLOGGING TRANSMITTER TASK 79-21-07 AND NEW FILTER ASSY IN BOWL. PERFORMED LEAK CHECK, NO LEAKS NOTED. EMCS CDU BITE NO FAULTS IAW AMM 79-21, TASK 806 & TABLE 71-00-00, NO BY PASS LIGHT NOTED NR 1 ENGINE.