warped front rotors?

[Ron Girouard]

About 3 months ago, I notice that my brakes were pulsing at about 20,000 miles, so I took it to my ford dealer (still under 3 year warranty). They charged me $45.00 to tell me what I already suspected, my front rotors were warped. They told me it would cost me $200.00 to machine the rotors to correct this problem. Now, I have an auto tech backgound and do not agree that rotors should warp when driven normally. Both, the dealer and Ford customer care did not want to repair this under warranty.:angry:

The heck with this, I decided I was going to repair it myself. Here are my findings:

When I pulled the rotors off, I notice that there were several bugs (grasshoppers, moths) blocking the cooling fins.

Can someone tell me if the ABS sensor is "looking" at these open fins or is it looking at something else? Can this confuse the ABS and pulse the brakes similar to warped rotors?

Anyway I took my rotors in to be machined by a jobber shop for $10.00 a piece and cleaned all the fins. They now work great. Any comments would be appreciated.

 

[EddieS'04]

The ABS sensors dont see the cool fins. They read the pulse ring on the back side of the rotors..... I agree normal driving should not warp the rotors. Some have said that the rotors on our trac are not the best quality...

 

[Tom Schindler]

Warped rotors are common on vehicles with pads that have high metallic content.



I recomend you either replace the rotors or have them turned and buy some good pads like Performance Friction Carbon Metaliic pads. If you have an auto tech background, you should be able to do it yourself.



Kiss your brakes problems goodbye.



For the record, I had my rotors turned for the first time at 54,000, or so, miles. I figure I might replace them at 100,000 miles, unless I mic them and they are still good. When I had them turned, they cut about .010 off the rotor.





Tom

 

[Richard L]

Spiker,

The ABS sensor is spaced about 0.020" off the ABS tone ring on the back of the rotors near the hubs and have nothing to do with cooling. The cooling fins are in the edge of the rotor disc and separte the inner and outter rotor surfaces. all Front rotors have those cooling fins and they have nothing to do with the ABS sensors.



Brakes are normal wear items and are not cover under the warranty except for the first 12 months or 12 miles. And yes, brake rotors will warp under normal driving. Hundreds of people have had to turn or replace rotors with less than 20K miles.



Having the rotors turned cured your pedal pulsing problem, however I hope you did a complete inspection and replacement of any questionable front brake components, and at least replaced the brake pads.



...Rich

 

[biznaga]

I read this forum too much. I recall similar question on warped rotors awhile back. Try link below:

 

[Michael Cacioppo]

In my opinion, rotors that are stessed relieved after machining should not readily warp if the stresses applied by the lugs are uniformly applied. Brakes and rotors should be what is called "bedded" to insure a good pad/rotor interface. Pad material actually covers surface of the rotors uniformly. Most people don't bed their brakes which I believe contributes to high spots, much of which is pad material. This aggrevates the warping procedure isasmuch as the applied heat pattern no longer is uniform when braking. Cutting rotors reduces their thickness and mass and contributes to higher brake rotor temperatures since the heat sump (rotors) no longer has the same capacity. Most of the time if the original had more than amble mass, this is not really a large factor.



You are right about the rip off prices that many places charge when brakes are involved. as you know the job is not that difficult and rotors usually do not require cutting if they have not been warped.



That's my opinion.