THE ORIGINAL TRAILER COUPLER/SURGE BRAKE ACTIVATOR ON MY APPROXIMATELY 15 YEAR OLD TWO AXLE BOAT TRAILER (LOADRITE AB 24-4000 WAS PROFESSIONALLY REPLACED DUE TO THE FAILURE OF THE HYDRAULIC SURGE BRAKE ACTUATION MECHANISM IN THE ORIGINAL COUPLER. THE TRAILER WAS CARRYING ITS USUAL LOAD ' A VINTAGE 1959 LYMAN WOODEN BOAT THAT HAS BEEN CARRIED ON THIS TRAILER TO MANY ANTIQUE BOAT SHOWS AROUND THE EASTERN UNITED STATES. THE WEIGHT OF THE TRAILER AND BOAT IS ESTIMATED AT ABOUT 4500 LBS. THE NEW COUPLER WAS A TITAN BRAND COUPLER RATED AT 6000LBS AND WITH NO MODEL NUMBER INSCRIBED. THE COUPLER IS UNUSUAL (AT LEAST TO ME) IN THAT IT ENTAILS A KNOB ON THE TOP INTENDED TO BE HAND TIGHTENED TO BRING THE RETAINER PAWLS IN CONTACT WITH THE UNDERSIDE OF THE TRAILER BALL, THEREBY SECURING IT FOR TRAVEL, RATHER THAN THE MORE COMMON LEVER ACTION DEVICE WITH ITS POSITIVE LOCK WHEN, AND ONLY WHEN, THE LOCKING PAWL IS FULLY ENGAGED. THE INSTALLER CONDUCTED THE USUAL TESTS, INCLUDING BLEEDING OF THE BRAKE LINE AND REPEATED TESTING OF THE ACTUATOR MECHANISM. ON JULY 29 I ATTACHED THE TRAILER TO MY USUAL TOW VEHICLE ' A 2011 TOYOTA TACOMA ACCESS CAB 4X4 EQUIPPED WITH AN OFF ROAD SUSPENSION AND FACTORY TOWING PACKAGE. THE TRUCK WAS RATED TO TOW 6500 LBS. THE FIRST 150 MILES NORTH ON INTERSTATES 93 AND 89, VERY FAMILIAR ROUTES, PROCEEDED UNEVENTFULLY WITH THE BOAT AND TRAILER TOWING WITHOUT DIFFICULTY.