Till the Wheels Fall Off: Mazda Recalls 2019 Mazda3 for Risk of Wheel Departure

Mazda has filed a recall for 25,003 of its 2019 Mazda3 cars due to a risk of the wheels falling off. Lug nuts were found to have loosened and come off the car, though there have been no reports of accidents or injuries thus far. Having personally had wheels depart my cars more than once, I can attest to this leading to a less-than-ideal day and hope to encourage affected customers not to wait on this one.

Wheel bolts, or studs, on the car are pressed in from the back of the wheel hub. When the lug nuts are tightened on the studs, they essentially sandwich the hub, rotor, and wheel together. Mazda found that the studs where not fully seated in the back of the hub as the vehicles left the factory, allowing them to be drawn in the remainder of the way as the forces on the wheel were naturally applied through driving. This, however, would also gradually reduce the torque on the lug nuts.

The torque checks for the lug nuts at the factory passed, as the force applied was presumably less than what would be required to draw the studs the rest of the way into the hubs. That’s why this wasn’t caught during assembly. As the cars would be driven and lateral forces were applied, studs would become fully seated in the hubs.

While the original issue was self-correcting, the lug nuts would eventually lose their torque in this process. Mazda’s correction is thus to simply re-torque the lug nuts and send the customer on their way.

From the day of the first report being received (April 9, 2019), it took Mazda another 10 to implement temporary countermeasures inside its plants in Japan and Mexico. Simultaneously, the company was able to address the root cause at the supplier who pressed the studs into the hub assemblies. The issue was fully resolved by May 3, 2019 and the decision to issue a “proactive field action” on affected MY2019 Mazda3 vehicles was made on May 30th. While the countermeasure at the supplier was officially implemented by April 22nd, it likely took until May 3rd for the affected parts stream to fully cycle through the vehicle assembly plants.

According to the NHTSA recall report, owners with the vehicles at risk will have a VIN ranging from JM1BPACM2K1100042 to JM1BPAMM0K1136438. It is advised that they have their wheels re-torqued at their local Mazda dealer as soon as possible. A rattling noise may occur before the complete loss of a wheel or lug nuts, so owners should be listening for this or sensing for any unusual vibrations while driving until they have the issue resolved.

Losing a wheel is no joke and I’ve unfortunately had it happen a few times, though in much harsher environments. I had wheel stud failure in an E36 328is I was racing in American Endurance Racing at Mid-Ohio last October. It did not end well.

[Images: Mazda]