B727 CREW INBOUND TO OAK RWY 29 ARE ALERTED BY O90 CTLR TO CORRECT FROM A FALSE LOC SIGNAL THE SAME TIME THE FLC IS CHKING LOC VALIDITY.

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WE WERE SW OF THE ECA VOR ON THE MADN 4 ARR TO OAK. BAY APCH ASSIGNED US TO FLY A 220 DEG HDG UNTIL INTERCEPTING THE RWY 29 LOC. THE AUTOPLT WAS ENGAGED AND WE RECEIVED A GOOD IDENT ON THE LOC. THE ACFT TURNED TO A 270 DEG HDG AT THE TIME OF LOC CAPTURE AS INDICATED ON THE FLT DIRECTOR AND AUTOPLT ANNUNCIATORS. ALTHOUGH NOT VISUAL WITH OAK; WE SUSPECTED THAT THE AUTOPLT/FLT DIRECTOR MIGHT HAVE LOCKED ON TO A FALSE LOC SIGNAL. OUR COMPANY HAS EXPERIENCED NUMEROUS FALSE LOC CAPTURES WITH RWY 29 LOC AT OAK. WHILE THE FO XCHKED OUR POS WITH THE OAK VOR; ATC QUERIED US AS TO OUR HDG. WE RESPONDED '270 DEGS.' HE TURNED US BACK TO 240 DEGS UNTIL INTERCEPTING THE LOC. I DISCONNECTED THE AUTOPLT AND FLEW AN UNEVENTFUL APCH AND LNDG. THIS CONTINUES TO BE AN ONGOING PROB AT OAK WITH THE RWY 29 LOC. ADDITIONALLY; OUR ASSIGNED INTERCEPT OF 220 DEGS VERSUS THE 294 DEG FRONT COURSE MIGHT HAVE CONTRIBUTED TO THE EVENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED THAT ALL COMPANY ACFT HAVE RPTED THIS PROB AND IS NOT REPRESENTATIVE OF 1 ACFT TYPE ONLY; THOUGH APPARENTLY MORE COMMON IN THE DC10. CALLBACK CONVERSATION WITH TWR SPECIALIST REVEALED THE FOLLOWING INFO: ADVISED THAT IT HAS BEEN AN UNRESOLVED PROB FOR OVER 1 YR. THE SPECIALIST STATED THAT THIS PROB HAS BEEN RPTED BY JUST 1 ACR. MAINT HAS SUGGESTED THAT USAGE BEYOND THE LOC SIGNAL LIMITATION (THOUGHT TO BE 18 MI) MAY HAVE SOME INFLUENCE ON ACFT COURSE DIVERGENCE; BUT NO SIGNIFICANT CORRECTION TO THE ILS EQUIP HAS BEEN MADE.