How to fix brake lock up – Nissan Mercury
Shops are reporting brake lock-up problems on the Nissan Quest and Mercury Villager with ABS brakes (up to the 2002 model year). The problem is caused by contaminated brake fluid blocking the ABS valves, especially the dampener valve. The dampener valve is screwed into one of the outlet ports on the master cylinder. The left front and right rear brakes line is attached to this valve. When these valves get plugged, they don’t release brake pedal pressure.
Before you perform the fix mentioned here, first remove the fasteners holding the master cylinder to the firewall. Then pull it forward slightly to check the push rod adjustment. If the push rod isn’t adjusted properly, it won’t allow the master cylinder to return to full off position. The fix is crack open the line attached to the dampener valve. If that releases the brake fluid pressure, you’ve found the cause of the problem. Flush the entire brake system with new fluid. If the problem still exists, replace the dampener valve.
© 2012 Rick Muscoplat