AS THE MCDONNELL DOUGLAS DC8 CREW BGN THE AFTER LNDG CHECK, A DECREASE IN QNTY OF HYD PRES WAS NOTED. THE CAPT ELECTED TO LEAVE THE FLAPS EXTDD, THOUGH THE SPOILERS WERE RETRACTED. HYD PRES RMND NML & THE CREW CONTD TO THE RAMP. WHILE TAXIING, THE QNTY SUDDENLY WENT TO ZERO; THE NOSEWHEEL STEERING & NML BRAKES BCM INOP. ATMTS TO STOP BY USING EMERG PNEUMATIC BRAKING WERE UNSUCCESSFUL. THE CAPT TRIED TO REVERSE THRUST FM #2 & #3 ENGS, BUT THEY WOULD NOT REVERSE (#1 & #4 ENGS WERE SHUT DWN). THE ACFT WAS ON A SLOPE; IT SUBSEQUENTLY ROLLED INTO A BOEING 727. AN EXAM REVEALED THE BOGIE TRIM CYL, PN 5616554-5503, ON THE L MAIN LNDG GEAR HAD RUPTURED. THE AIR BOTTLE FOR PNEUMATIC BRAKING WAS CHARGED TO OPERG PRES, BUT MOVEMENT OF THE AIRBRAKE LEVER WOULD NOT OPER THE CTL VLV, PN 25600-5001; THOUGH NO ANOMALIES WERE FND IN RIGGING/ALIGNMENT. MANUFACTURER DIDN'T PROVIDE A RCMDD INTERVAL FOR CHECKING THE PNEUMATIC BRAKING SYS, BUT THE OPER-ATOR CHECKED IT AT 25,000 HR (D-CHECK) INTERVALS; THE ACFT HAD BEEN OPERD 19,339 HRS, SINCE THE VLV WAS LAST CHECKED.