The ABS tone rings on the 2008 model Mercury mariner and Ford escape are defective in design - they are thin metal, but put under stress by being forced onto the half-shaft (different metal, different expansion rate), and therefore prone to cracking/breaking. When cracked/broken, they cause the ABS brake system and regenerative braking to fault out, sometimes intermittently and with no warning. The part itself is cheap (~$10 each), and apparently should be, but the dealer will not sell them separately, and instead requires the owner to replace the half-shaft, with estimates from the dealership and independent mechanics of between $400 and $1000 to replace both front half-shafts. Simply making the part thicker, or of the same metal as the half-shaft, would fix the problem - instead, Ford forces owners to choose between an unsafe vehicle and robbery, with no guarantee that the problem wouldn't recur within a month of driving (the cracking seems to be more related to temperature than mileage). This should be recalled and Ford should be forced to replace these at their own cost - I bet they'd then "discover" a way to prevent recurrence if they were paying out of their own pocket for any that failed before 100,000 miles. A cursory search on the internet will turn up thousands of results for this problem.

- Alexandria, VA, USA