[PupsterDO]

When I am on the highway and going anywhere above 60 and have to stop fast, when I step on my brake, my steering wheel shakes a little bit. I had this same problem before I got new front brake pads and rotors and my mechanic told me that the old rotors were warped over their then > 45000 miles. Now I have about < 52000 on the Escape with new rotors. Are my rotors warped again after less than 7000 miles? If so, is there anyway to straighten them out without taking it to get new rotors which, obviously, I don't think is reasonable with such low mileage on the new ones?

 

[Squishy]

Does your mechanic use a torque wrench, or even a torque-stick, to tighten your lug nuts?

If not, ask him to retorque your lug nuts or find a mechanic who does propery torque things down. A wheel attached with uneven torque distributes uneven stress to the brake rotors, which will lead to warping. It sounds as if you have a very minor case that is only noticeable at high speeds, so the rotor might straighten out on its own after the lug nut torques are fixed (if that indeed is the issue).

Although the problem doesn't happen as soon as 7000 miles, I almost always get some high speed vibrations in rotors more than a few years old.

 

[jpark]

Good point. I use a torque wrench (KD Tools 85054) that clicks when it reaches the torque level you set. That way, all of the lug nuts have the same torque on the hub, and that takes away at least one source of rotor warp.

 

[PupsterDO]

My wheels need to be rotated anyways in probably another 2000 miles or so. I'll make sure when that happens that whoever does the rotation (hopefully my dad) torques them properly. To tell you the truth, I don't know if the mechanic who put my new tires on right after I got the new brakes torqued them properly...

 

[PupsterDO]

Would the extra 2000 miles til my next rotation (80% highway) make a difference? Should I get this taken care of right away?

 

[jpark]

I'd take care of any vibration right away, but that's me.

Most mechanics use impact wrenches, since it takes only three seconds to tighten all of the lugs. Move 'em in, and move 'em out.

:rant:

There's a local tire chain here that uses only torque wrenches to tighten the lugs. They'll torque the lugs when they install your wheels and tires, then they give you a coupon to bring the car back in two days so that they can "touch up" the torque levels.

 

[PupsterDO]

I noticed this vibration when braking on my way to work today. It was raining today though. Would rain have any effect on there being a vibration?

 

[Squishy]

Rain sometimes exacerbates the problem if the rain is very heavy or the roads have decent puddles collected on them. Water splashing on hot brakes creates uneven cooling which warps the discs. Fortunately, all of my cases where my rotors warped in the rain were temporary - they evened out again after the brakes dried up.

I don't know how this slipped my mind, but did you bed in the new brakes? Warping can be caused by uneven brake liner deposits on the rotor as well as actual warping of the steel. Most brake pad manufacturers recommend something like "ten firm stops from 30 MPH, followed by a cooling period (few miles of driving will do), followed by five firm stops from 50 MPH". This evenly distributes a layer of brake pad material on the rotors.

 

[PupsterDO]

Rain sometimes exacerbates the problem if the rain is very heavy or the roads have decent puddles collected on them. Water splashing on hot brakes creates uneven cooling which warps the discs. Fortunately, all of my cases where my rotors warped in the rain were temporary - they evened out again after the brakes dried up.

I don't know how this slipped my mind, but did you bed in the new brakes? Warping can be caused by uneven brake liner deposits on the rotor as well as actual warping of the steel. Most brake pad manufacturers recommend something like "ten firm stops from 30 MPH, followed by a cooling period (few miles of driving will do), followed by five firm stops from 50 MPH". This evenly distributes a layer of brake pad material on the rotors.

Should I try this even after 7000 miles of driving and stopping?

 

[Squishy]

I can't give you a definite answer on that, because I have never tried it nor read of anyone trying it.

You could give it a try; I don't think that it would make the problem any worse. One thing I forgot to add - you don't actually stop, but you do slow down to about 5 MPH before accelerating back up to 30 or 50 MPH. Coming to a complete stop would not let the area under the pads cool off and "melts" the pad to the rotor.