A B767-300ER WAS RPTED BY THE FO AS NOT PASSING A STABILIZER TRIM PREFLT TEST THAT IS NOW DELETED FROM THE PREFLT COCKPIT CHK PROCS.

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AT ONE TIME OUR PREFLT CHKLIST PROVIDED FOR CHKING THE STABILIZER TRIM BRAKE. THIS CHK INVOLVED TURNING ON THE HYD PUMPS; RUNNING THE STABILIZER TRIM; AND THEN MOVING THE YOKE IN OPPOSITE DIRECTION OF TRIM INPUT; WHICH OPERATED THE STABILIZER TRIM BRAKE; THEREBY STOPPING THE TRIM MOVEMENT. THIS ITEM WAS REMOVED FROM OUR PREFLT CHKLISTS; AND IS NOT DESCRIBED IN OUR OPS MANUAL. I STILL DO THESE CHKS ANYWAY; AND BELIEVE THAT 1 STABILIZER TRIM BRAKE IS INOP ON SHIP. WHEN THE TRIM IS RUN UP; AND YOKE PUSHED FORWARD; THE TRIM STOPS. HOWEVER; WHEN RUNNING NOSE DOWN TRIM; AND THEN PULLING BACK ON THE YOKE; THE TRIM DOES NOT STOP. SINCE THIS CHK IS NO LONGER PART OF OUR CHKLISTS; AND NO INFO ABOUT IT IS PROVIDED IN OUR OPS MANUAL; AND SINCE THE TRIM DID SLOW NOTICEABLY; ALTHOUGH NOT STOPPING COMPLETELY; THE CAPT DID NOT WRITE IT UP; BELIEVING NO DISCREPANCY EXISTED. A MECH WAS QUESTIONED ABOUT IT; BUT HE WAS NOT KNOWLEDGEABLE ABOUT THIS SYS; AND LEFT IT UP TO THE DISCRETION OF THE CAPT AS TO WHETHER IT NEEDED MAINT ACTION. I JUST LEARNED ABOUT ANOTHER PLT'S EXPERIENCE WITH AN ACFT THAT INVOLVED SOME ERRATIC FLT CTL INPUTS DUE TO A PRESSURE SWITCH PROB AND THE STABILIZER TRIM BRAKE; AND BELIEVE THIS PREFLT CHK SHOULD BE PLACED BACK IN THE CHKLIST.