Our 99 Explorer XLT had a grinding noise when braking hard. Thought it might be a wheel bearing. Droped it off a Ford dealer Sunday evening for a slow leak in L.R. tire and rotation. Picked it up Monday note on bill, need pads front & rear plus rotors. Went and picked up pads and rotors amd installed them last night. Front pads were just below wear bar, rear had about 1/4" left. Front rotors needed turned so installed new. Rear were fine so didnt replace them. Now when the grinding noise was happening road was dry. A little while ago when I test drove there's about a 1/2" snow on road a steering wheel as a shimmy when turning to the right. Left turn is fine. Before I tore it down I tried to move the front wheels pushing on top and pulling on bottom of tire. No movement either side. Is that a bad hub bearing on the right side. Thanks in advance..

 

First thing to confirm is that the lugnuts have been properly torqued. Assuming the torque is good, did you happen to turn the steering knuckles when changing the rotors and pads without the engine running? You might have some air in the power steering lines causing the shake on right turns. If so, once the air works its way out, the steering feel will be back to normal.

-Rod

 

I did turn the wheels changing pads & rotors. Didn't know that would cause a problem. Thanks for the reply.

 

It doesn't necessarily cause a problem, but if you turn the wheel too fast you can introduce air in to the power steering system if the engine is not running when you steer the wheels.

-Rod

 

Rod, I'm not doubting what your saying, but I 'I've put pads on before and turned the wheels doing so with no ill effects. Today the roads were clear and SWMBO said it steered fine. Might should of mentioned that it's AWD. As said earlier the hub bearing seems to have no free play, ball joints were replaced a while back. Possibility something binding in the axle.

Dave

 

Sure, it could be something binding in the driveline, and without being able to experience the "shimmy" it's hard for me to gauge if it feels more mechanical than hydraulic. But going off the clues provided:

• No concern of shimmy prior to brake replacement
• Wheels were steered manually during brake replacement, which can introduce air in to the system that will work its way out
• No other looseness in steering/suspension detected
• Immediately after brake replacement the shimmy could be felt on dry pavement
• A few days later the shimmy is no longer present on dry roads.

Since it seems to be getting better based on the information provided, air in the power steering system still seems reasonable. As a matter of, at a minimum, preventive maintenance, you could replace the fluid in the front and rear differentials as well as the center VCU/transfer case and see if any of the fluids give an indication of mechanical issues.

-Rod