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From the symptom description, the pressure is not being released and it could be form the master cylinder or ABS accumulator.
To identify the source, when problem occurs, loosen the master cylinder brake pipes and if the brakes releases, the fault lies with the master cylinder. If the brakes does not release, then the fault would be with the ABS accumulator.
ABS Accumulators tends to fail over time if it has been diasbled without being removed from system.
Thursday, August 31st, 2017 AT 11:05 AM