Rotors just turned....now pulsating

[sounderella]

So I just bought a used 2011 Edge from a Ford dealership. I had noticed on the Carfax that the dealership had turned the rotors and replaced an axel ring prior to listing for sale. During the test drive I noticed that the rotors were not up to par....there was significant wobble. So either 1 of 2 things happened. The rotors didn't get turned or whoever did it, didn't do a good job. Not a biggie, just made the dealership turn them as terms of the sale.

 

Leaving the dealership, everything felt great...no more wobble. Now, four days later, I've got the pulsating action during braking.

 

So the question is, do you think it's the calipers not sitting correctly, dirty speed sensor possibly?

 

Thanks for any help!

[Feirstein]

With newly turned or new rotors one needs to transfer a bit of pad material onto the rotor surface. This is usually done by taking few mild and repeated stops and then driving to cool the rotors down without keeping the pads in contact with the rotor until they had a chance to cool down a bit.

 

Try this procedure to see if you can even out the pad material on the rotors. If this does not work you might want to run some appropriate sanding material on the rotor surface and try again.

[akirby]

Check the torque on the lug nuts. Uneven torque will cause the same problem.

[autom8r]

Sounderella,

 

Congratulations on your purchase. The Edge is a great car. Here's what you may need to know about your rotors.

 

Rotors warp with heat, kinda like a frisbee that is left in the sun too long. That pulsation you feel is the brake rotor fighting against the caliper. Front rotors usually warp before the rear rotors do. Braking is 70% front, 30% rear {approximately}.

 

Bear in mind that the thinner the rotor becomes, the more susceptible it becomes to heat deformation [warping]. The Edge is a heavy car and to stop it requires a great deal of energy, all of it converted to heat during braking and dissipated to the environment by the braking system, the rotors being the chief component of the heat dissipation system.

Rotors have a minimum allowable thickness. The minimum thickness specification is sometimes stamped in the edge of the rotor for your convenience. So long as the rotor is greater than the minimum allowable thickness, it can be cut, and re-cut, and re-cut ad-nauseum. A dealer may choose to cut [turn] the rotors rather than replace them if the rotor still has enough meat on it.

 

Ford recommends an "on vehicle" brake lathe. This is a labor/time saving device, though I prefer the bench lathe, somehow I can't get past the self-calibrating anti-wobble run-out feature of the on-vehicle lathe. I suppose it can compensate for a bent axle though. It may help the dealer make his decision because it is easier to leave the rotors on the car. With a bench lathe, the rotors need to come off, same labor to install a new one as a cut one.

 

I've attached a section of the service manual for your use. It is for a first generation Edge, and may also apply to yours. It notes the minimum thickness requirements of the rotors.

 

A caveat, all of the preceding comments are also correct, and may also be the solution to your dilemma.

 

Good luck!

Ford Edge Brakes Info.pdf

[carbonedge+]

Check the torque on the lug nuts. Uneven torque will cause the same problem.

Ditto...or could be evenly over-torqued lug nuts...I believe the specs call for 100 ft/lb.