1637 Reported internittent stuck brake. ~~~~~ 1637 Reported internittent stuck brake.     When 750 vdc cut off,ACU slow release.Air leaking from exhaust port.Replaced ACU and carried out brakes cyclic/function test ok. ACU-Old s/n: 1503-070  New s/n: 1528-130 Not: 2128830 Raise. Done by Kumar/Jack/Sateesh. 07/02/20