When I brake, there is a loud rumble from the rear as if the ABS is engaged under all circumstances and all speeds. The rumble will dissapate as the car slows down then goes away when stopped. Could this be a controller problem or a sensor problem. I just replaced the rotors and pads on the rear ant the pads on the front. It is more pronounced since the rear brakes were replaced.

Thanks.

 

Were the Rotors Volvo parts.If not you may have to have them turned.Even new after market rotors may be warped.

 

This was happening before the new brakes were installed, they were original OEM. The noise would not fully dissapate until after a full stop, so I doubt that the rotors are causing the niose.

 

The rear rotors warp very easy because they are very thin.Most of the time aftermarket new rotors are warped and should be turned before installing.

 

OK, But why would the rumble continue after the car has stopped? I counted a full three seconds after the car comes to a full stop before the rumble goes away.

 

Maybe since is doesn't stop making noise till after you are already stopped you might have a dirty abs sensor.You can try removing the sensor and cleaning it and reinstalling it.

 

I cleaned the sensors and the problem is gone. The brakes are working properly now.

Thanks.

 

No problem anytime.That is not a common problem with the 850's.It was a common problem with the front sensors on the 740's.

 

I see only the ABS sensors in the front wheels. Are there sensors located in the rear wheels as well?

 

Yes there is sensors that mount into the back of the backing plate.