BRAKE LOCKED ON LNDG; ACFT NOSE OVER.

Narrative

CONVENTIONAL TAILWHEEL ACFT. LNDG ACCOMPLISHED XING THRESHOLD WITH ENG AT IDLE. FULL STALL 3 POINT LNDG WITH PLANE'S PATH STRAIGHT DOWN THE RWY. AFTER ACFT WAS SLOWING TO TAXI SPD ON LNDG ROLL; GENTLY APPLIED TOE BRAKES. BRAKE LOCKED AND WOULD NOT RELEASE WHEN THE PRESSURE REMOVED AND FOLLOWING HEELS ON FLOOR PRECAUTION. TAIL CAME UP FROM 3 POINT POS AND ACFT ALIGHTED ON ITS BACK. IGNITION; MASTER AND FUEL IMMEDIATELY SHUT OFF. NO INJURIES BECAUSE OF SHOULDER HARNESS THAT HAD BEEN ADDED TO THIS OLD ACFT. PLT'S INSPECTION AFTERWARDS INDICATED THAT ONE OF THE BRAKES WAS NOT MOVING FREELY AND USED LONG SCREWDRIVER TO PRY FREE. ALSO NOTED CONSIDERABLE CONTAMINATION ON BRAKE ASSEMBLY PINS AND SHAFT THAT PIN RIDES IN. ACFT IS INFREQUENTLY FLOWN AND TIED DOWN INSIDE. RECOMMEND REGULAR DISASSEMBLY INSPECTION AND CLEANING TO ASSURE FREE AND SMOOTH MOVEMENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR STATES ORIGINAL BRAKE COMPONENT WOULD NOT HAVE ALLOWED THIS TO OCCUR. IT IS A STRAIGHT CYLINDER ACTION. CONVERSION ON THIS OLD ACFT IS APPROVED AND CAME WITH THE ACFT. IT IS USED ON MANY OLDER ACFT. IT DOES; HOWEVER; HAVE A PIN WHICH CAN BECOME STUCK AND CREATE LOCKING OF THE BRAKE. IT IS EASIER TO WORK ON AND TO CHANGE LINERS. RPTR DOES NOT CONDEMN BRAKE; BUT NOTES THAT IT REQUIRES MORE ATTN. FILED RPT WITH NTSB WITHIN PROPER TIME FRAME AND WITH GRAPHICS SENT TO ASRS. RPTR CONCERNED BECAUSE HE FEELS HE MAY HAVE OVERSTEPPED THE LIMITS OF MAINT HE IS ALLOWED TO DO W/O A&P LICENSE.