Why are my new rotors and pads wearing like this?

[DennisF]

Why are my rotors and pads wearing only in the centers. It looks like I'm only getting about 60% of the potential braking, since the wear is occurring only in the centers while the inner and outer edges of the rotors are building rust. Please note in second picture that you can see the lower friction portion of the pad covering the inner ring of corrosion on the rotor. In the third picture you can compare/contrast the actual mating pad with the rotor surface and see that the friction portion of the pad covers significantly more of the rotor than the area of significant wear is indicating. It seems to me that since pad pressure is applied to all but the outer 1/4" and the inner 3/8" of the rotor, the rotor should display even wear throughout that portion of the surface.


Outside Surface

Outside surface with pads in place

Outside surface with view of the mated pad

Inside surface of the rotor - similar wear pattern

These rotors and pads were new in August of 2010. They have approximately 6500 miles. They are Wagner BD125469 rotors and Wagner Thermo Quiet QC652 pads. The OEM rotors that these replaced exhibited a similar wear pattern. The OEMs had approximately 96,000 miles. The caliper pistons seem to be moving freely, and the guide pins seem to be moving freely.

This is a 1998 Extra Cab, 2WD, 4.0L, with automatic trans.

I am baffled!

Thanks for your thoughts

DennisF

 

[TomB1269]

You could check different pad manufactures to see if there is any difference in pad width. However most of the issue is in the OEM design as you can see physically you can not install any larger pad in the pad caliper carrier.

 

[basilfaulty]

That is a typical wear pattern. I bet the width of the wear pattern is the exact width of the pad material.

 

[jrpdash9]

mine were wearing similar to that but after new calipers an pads it stoped

 

[DennisF]

OEM or other calipers and pads?

When you replaced the calipers and pads, did you use OEM, aftermarket replacement, or aftermarket premium, like EBC or Brembo?

Did you notice any change in braking, dust, or pad life?

Thanks,
DennisF

 

[ForOffRoadDriving]

looks like typical glazing to me, but that usually only occurs when people slap new pads on old rotors without cutting them. you said the pins seem to be moving, does this mean that you disassembled the brakes and pulled the pins out and pushed them back in to make sure they were greased and moving freely?

 

[DennisF]

Thanks for you thoughts.

Yes, these were new Wagner ThermoQuiet pads and new Wagner rotors, but the rotors were not cut after I received them.

Yes, I removed the guide pins, cleaned them, and re-lubed them. They were moving freely then, and they are moving freely now.

The caliper pistons are also both moving freely, although not smoothly throughout their entire range of travel. Each caliper has one piston that binds, just slightly, when extended about 1/4" from the bore. I have not disassembled the calipers and honed the bores.

 

[ForOffRoadDriving]

cutting new rotors shouldnt be necessary, but cleaning off all the packing oil IS. if the slides are sliding good and the pads are moving in the bracket freely then the only other things to look at are going to be the calipers and the hoses, which can deteriorate from the inside out and actually collapse after releasing the pedal, causing residual pressure to remain, in turn causing your pads to drag on the rotor and temper/ glaze both the pads and the rotors.