Troubleshooting Key That Wont Turn for Red Master Lock Trailer Coupler Lock

Updated 10/14/2019 | Published 10/13/2019

Question:

Key won’t turn on master lock “red” ball lock

asked by: Barb M

Expert Reply:

If you are having trouble unlocking the Master Lock Trailer Coupler Lock # ML389DAT then I recommend using a spray lubricant like WD-40 to help loosen up any dirt or grime that may have gotten in the lock. Let the spray sit in the lock for a few minutes and then try operating it again. If this still doesn't fix the problem then you may need to have a locksmith take a look at it.

expert reply by: Jon G