3556 - PARKING BRAKE RELEASE FAULT ~~~~~ To replace P.B pressure switch.  2556 replaced parking brake pressure switch. Function check & air leak check - OK. Parking brake able to apply and release. Limited movement/depot shunting - OK.  Sarma/Kamarul/Anand/Shafie 45376 3556 - PARKING BRAKE RELEASE FAULT.  3556 checked/found parking brakes unable to release causing Parking Brake Release Fault. Swapped parking brake valve but fault still remained. OPS 20 raised to follow-up.  Wong/Aqil/Akira 45374 To follow up rectify.  3556 found Parking Brake Fault. Physically checked all brakes able to release at COAST. Fault still persisted on TIMS. Swapped Parking Brake pressure switch from #3556 to #2556. Fault transferred to #2556 & fault cleared on #3556. Unable to replace #2556 PB pressure s/w due to old pressure s/w thread fatigue & broken inside. OPS 30 raised to replace PB pressure s/w on #2556.  Aliff/Daniel/Redzwan/Chan SW 45376