A BEECH 400B ON LNDG ROLLOUT LOST GND SPOILERS AND BRAKING. ACFT STOPPED WITH EMER BRAKING. CAUSED BY IMPROPER MAIN STRUT SERVICING.

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OUR BEECH JET 400 WAS SCHEDULED FOR PICK UP AFTER ITS 4500 HR LNDG GEAR OVERHAUL FROM MANUFACTURER SVC AT THE ZZZ1 ARPT ON SATURDAY; OCTOBER. WE ARRIVED (MYSELF AND THE CO-CAPT) AND BEGAN WORKING WITH THE AIRPLANE AND LOOKING FOR THE SUPVR; HE WAS UNDERSTANDABLY AT LUNCH. WE WORKED TO OPEN UP THE AIRPLANE; REMOVE ENG COVERS AND REMOVE BEFORE FLT FLAGS. IT TOOK SOME TIME TO FIND THE LOGBOOKS AND GET THE MAINT ENTRY INSTALLED IN THE BOOK. IN THIS TIME THE SUPVR ARRIVED. I TOLD HIM WE WERE MAKING HEADWAY WITH THE PRE-FLT AND WE BOTH TALKED ABOUT THE MAIN LNDG GEAR STRUT EXTENSION BEING HIGHER THAN WHEN IT ARRIVED. HE SAID IT WAS DUE TO THE PLANE 'BEING LOW ON FUEL'. I TOLD HIM IT HAD BTWN 800 AND 1000 LBS WHICH IS WHAT WE USUALLY LAND WITH. AND I REMEMBER ASKING SPECIFICALLY; 'YOU ARE SURE THAT THE STRUTS WERE SERVICED IN ACCORDANCE WITH THE MAINT MANUAL?' HE SAID; 'YES; I AM SURE. IT'S JUST BECAUSE THERE IS NOT MUCH FUEL IN THE AIRPLANE THAT THE STRUTS SEEM HIGH.' WE ORDERED A FUEL TRUCK AND A GND POWER UNIT AND CONTINUED RUNNING THE PRE-START CHECKS. ALL OF THE PRE-START CHECKS (WHICH INCLUDE THE ANTI-SKID WARNING SYSTEM); WERE NORMAL. ENG STARTS WITH GPU POWER WERE NORMAL. OUR CLRNC WAS OBTAINED AND TAXI COMMENCED. ALL PRE-TAKE OFF CHECKS SHOWED ALL SYSTEMS OPERATING NORMALLY (THESE CHECKS INCLUDE THE SPEED BRAKES; ANTI-SKID; AND NORMAL BRAKING). THE FLT HOME WAS UNEVENTFUL AND NORMAL. ON WEDNESDAY; OCT WE FLEW 1 PAX TO ZZZ2 AND ZZZ3 THEN EMPTY BACK TO HOME BASE. ALL CHECKS ON ALL LEGS SHOWED NO ABNORMALITIES ON ANY CHECKS. ALL SYSTEMS APPEARED TO BE WORKING NORMALLY AND SAFELY. ON FRIDAY; OCT OUR FIRST LEG INVOLVED 8 PASSENGERS. WE WERE EMPTY BACK TO HOME BASE. NO FLTS AROSE DURING THE REMAINING COURSE OF THE DAY; AND WE DEPARTED TO ZZZ THAT EVENING. AGAIN; ALL CHECKS SHOWED NO ABNORMALITIES; AND ALL SYSTEMS APPEARED TO BE OPERATING NORMALLY AND SAFELY UNTIL OUR LNDG AT ZZZ. ALTHOUGH NO REGULATIONS WERE BROKEN; I FEEL SUBMITTING A NASA FORM IS PRUDENT FOR TWO REASONS. FIRST; WHEN TALKING WITH THE INSTRUCTORS THAT SPECIALIZE IN BEECH JET TRAINING; THEY SAID THAT MY DESCRIPTION WAS IDENTICAL TO 5 OR 6 OTHER DESCRIPTIONS FROM CREWS THAT HAD OVER SERVICED MAIN LNDG GEAR STRUTS. ALL OF THE OTHER CREWS WERE ASSURED THAT THE STRUTS WERE PROPERLY SERVICED; AND HAD NO WARNINGS UNTIL THEY HAD A PROBLEM. CLEARED TO LAND AT ZZZ ON 28L NUMBER 2 BEHIND A SINGLE-ENG CESSNA. THE CESSNA CLRED THE RWY BY THE TIME WE WERE ON ABOUT A 2 MI FINAL. OUR LNDG TOUCH DOWN WAS NORMAL. AT TOUCH DOWN; AS THE PNF; I EXTENDED THE SPEED BRAKES. THE SPEED BRAKE SWITCH FELT 'DISCONNECTED.' I SAID; 'THE SPEED BRAKES DID NOT EXTEND'. WE ARE TAUGHT IN TRAINING THAT IF YOU LOOSE YOUR SPEED BRAKES; YOU MAY HAVE ALSO LOST YOUR WHEEL BRAKES. I SAID; 'DO YOU HAVE WHEEL BRAKES?' THE PF SAID; 'I GOT NOTHING. I'M GOING FOR EMER BRAKES.' WE ARE ALSO TAUGHT THAT DISCONNECTING THE ANTI-SKID SYS MAY RETURN BRAKING ACTION; BUT WITHOUT ANTI-SKID SYS. I SAID; 'I'M TURNING OFF ANTI-SKID.' THE PF SAID; 'I GOT BRAKES NOW.' WE STOPPED THE BEECH JET BY THE END OF THE RWY. WITH ABOUT 200 REMAINING I NOTICED THE SPEED BRAKES HAVE NOW EXTENDED. I SAID; 'THE SPEED BRAKES ARE EXTENDED; I'M TURNING BACK ON THE ANTI-SKID.' AS WE TURNED TO EXIT THE END OF THE RWY; WE FELT AN AGGRESSIVE SHAKING FROM THE UNDERSIDE OF THE PLANE. I SAID; 'FEELS LIKE WE BLEW A TIRE. CAN WE MAKE IT OFF RWY?' ATC WAS JUST THEN ASKING IF WE NEEDED ASSISTANCE. I ASKED THEM TO 'STANDBY.' THE PF SAID; 'NO WE CAN'T KEEP GOING.' I ASKED ATC TO DISPATCH A TUG; AND STATED THAT IT WAS JUST THE CREW ON BOARD; AND THERE WAS NO NEED FOR MEDICAL ASSISTANCE. ATC ACKNOWLEDGED THAT THE TUG WAS ON THE WAY. THE TUG WAS CONNECTED AND TUGGED THE REMAINING BIT OFF THE RWY (ABOUT 40') ON THE RUBBER OF THE DEFLATED TIRES (BOTH TIRES HAD BLOWN). THE RWY WAS CHECKED FOR FOD; AND ONLY ONE PIECE OF RUBBER ABOUT THE SIZE OF A MATCH BOOK WAS FOUND. TO THE BEST OF MY KNOWLEDGE THE RWY WAS REOPENED AT THAT TIME. CALLBACK CONVERSATION WITH RPTRREVEALED THE FOLLOWING INFO: THE RPTR STATED THE AIRPLANE WAS A BEECH 400 B MODEL OF WHICH 65 ACFT WERE BUILT AND HAD A FEW DIFFERENCES FROM THE BEECH 400 A MODEL. THE RPTR SAID ONE OF THE MAJOR DIFFERENCES BTWN THE MODELS IS THE MAIN GEAR STRUT PRESSURE FOR THE 400 A MODEL WHICH IS 250 PSI AND FOR THE 400 B MODEL IS 110 PSI. THE RPTR STATED MAINT FOUND THE MAIN STRUTS SVCED TO A MODEL A PRESSURE OF 250 PSI ALLOWING EXCESSIVE STRUT EXTENSION AND NOT ALLOWING GND SENSING SQUAT SWITCHES TO ACTIVATE. THE RPTR SAID FAILURE OF THE GND SENSING SYSTEM CAUSED THE GND SPOILERS NOT TO DEPLOY AND THE ANTI-SKID BREAKING SYS TO NOT OPERATE. THE RPTR STATED THE EXTENT OF THE ACFT DAMAGE WAS TWO BLOWN MAIN TIRES. THE RPTR SAID FLT TRAINING INSTRUCTORS ADVISED THE RPTR IN A TRAINING CLASS OF FIVE OR SIX INCIDENTS OF OVER SVCED STRUTS AND THE PROC OF SWITCHING OFF THE ANTI-SKID SYS TO RECOVER NORMAL BRAKING WHICH WAS TRIED IN THIS EVENT. THE RPTR STATED THIS WAS THE FOURTH FLT OF THE ACFT AFTER LNDG GEAR OVERHAUL AND THE ABNORMAL STRUT EXTENSION WAS NOTED AND BROUGHT TO THE ATTENTION OF THE MAINT SUPVR.