I owned a mercedes A160 year 1998. Recently, my brakes jammed and the mechanic told me to replace the wheel cylinder pump inside the drum brake as the rear brake is drum brake. When it is replaced the problem still occur and the mechanic told me it is the ABS pump. I still have doubt whether the ABS pump or the ABS sensor is the root cause of this problem. There are no warning light came out when the problem occured. Can anyone help me on this issue?