What was found
AIRCRAFT WAS GROUNDED: AFTER ENGINE START COCKPIT BRAKE PRESSURE INDICATOR INDICATED 2000 PSI. THERE WAS NO MOVEMENT ON THE GAUGE WHEN TURNING ON AND OFF HYDRAULIC PUMPS. THERE WAS ALSO A STRANGE NOISE DURING SOMEB RAKE APPLICATIONS ASSOCIATED WITH A SLIGHT VIBRATION IN THE RUDDER PEDALS. AIRCRAFT RETURNING TO THE GATE. ADJUSTED BRAKE CABLE TENSION, PER J/C 08L00032007 AFTER ADJUSTMENT OF CABLE TENSION, PERFORMED PARKING BRAKE HOLD CHECK AGAIN, PRESSURE BLEED DOWN WITHIN LIMITS.