1997 Taurus SHO rear brake, or perhaps bearing problem

[SkurdalenFox]

There has been a problem with the RR brake or maybe bearing on this car that no mechanic has been able to solve. This car has rear disc brakes.

Occasionally the RR brake, or bearings, or something make a terrible “waa-waa-waa” noise. The noise occurs randomly but frequently; usually on the high-way. The noise is wheel speed specific – faster speed results in faster frequency of the “waa-waa-waa” noise. If you tap the brakes, it’ll go away for a second, but come right back. If you steer to the left – change lanes – it’ll go away, but if you steer back to the right, it usually comes back. It seems to happen more frequently when on a road pitched to the right. If the road is crowned in the center, and you’re in the left lane – the road is pitched to the left – it doesn’t happen as frequently. Of course being in the fast lane results in speeding all the time.

The RR caliper and rotor have been replaced. I have no idea if the anti-moan brackets were installed or if the pads were shimmed properly. The mechanic said that it was a “loaded” caliper. I think that means everything, the pads and so forth, are pre-installed and therefore setup correctly.

Any ideas?

[04 Mach1]

If it changes with speed and turning in toward the wheel it goes away its the wheel bearing.

[SkurdalenFox]

Thanks, I'll pass the info along.

Is there a way to measure the hub's run-out?

Would it provide any sort of useful information to put a dial indicator on the face of the hub - where the studs stick out - give the hub a spin, and measure the variance?

[04 Mach1]

You can but most of the ones I've checked the hub run out was ok. most of the time its just due to a sealed bearing losing its lube that causes the waa waa waa noise.

[SkurdalenFox]

Thanks for the information.