If a brake system is inadvertently serviced with the wrong type of hydraulic fluid what must be accomplished?

• A. Drain and flush the system
• B. Replace seals
• C. Refill with correct fluid
• D. Inspect for contamination

Answer: (A)

When the brake system is exposed to a hydraulic fluid that isn’t compatible, the priority is to remove that incorrect fluid and any contaminants from the entire circuit. Draining and flushing accomplish this by emptying the reservoir and lines and then pushing through the proper fluid to purge out all residues. Simply replacing seals or refilling with the correct fluid without flushing could leave trace amounts of the wrong fluid in the system and fail to prevent continued incompatibility or damage. While inspecting for contamination and replacing seals may become necessary if damage is found, they do not on their own remove the wrong fluid from the system. Draining and flushing directly addresses the root issue and sets the stage for proper refilling and bleeding.