Q Recently a tone ring on my 2007 Ford SUV cracked and fell off. The dealer said replacing the entire front halfshaft was the only option. What a waste of a perfectly good shaft. Can I weld the ring and, if so, what can be used to reattach it to the shaft – epoxy?
A Tone rings are central to the operation of traction-control systems. For your particular vehicle, they’re on the end of
the halfshaft that connects the transmission to the wheels, riding on the constant velocity joint housing. A tone ring looks like a gear and fits on or near the hub of each wheel of a car. A sensor sits near the ring and detects the presence or
absence of one of those gear teeth. By calculating how fast the teeth are moving, the car’s computer knows how fast
each wheel is turning. After comparing the wheel speeds with what it expects to see, the computer decides if any wheels
are slipping under acceleration or braking and makes corrections with the brakes and/or the engine output. Because the
ring cracked and fell off, the car can’t tell what’s going on at that corner, leaving the antilock brakes and stability- control
systems hobbled. Needless to say, the problem should be fixed.
I know it’s tempting to try a cheap fix like glueing the ring on again, but trust me, it’s not worth the effort. I called some parts stores and found you could buy reasonably priced remanufactured front axles after a core return. If you take in the old damaged part you get a partial refund. Remanufacturers take the damaged parts and tear them down, clean up the main components and rebuild them for future customers. With basic know-how, some simple tools, and maybe a good service manual, changing a halfshaft takes just a few hours in your driveway. You get a good-as-new part, and that otherwise perfectly good axle will see another life.