Warped rotors

2016 4Runner with 97k miles. Dealer replaced front rotors and pads at 78k miles. At 89k miles, I got a pulsing upon braking and it felt like the front, so I replaced the front rotors & pads. The pulsing continued so I assumed the rear. I replaced the rear rotors & pads at 92k miles and the pulsing went away. Now, at 97k miles, pulsing returned! Is there any way to tell if front or rear, or which side would be causing?? What to try next?? p.s. just around town highway driving; no towing, no off-road.

 

For pulsing rotors, best way to tell if they are front or rear is to put one finger on the steering wheel while applying the brakes. If you feel it in the steering wheel, it's the front. If you feel it in the seat, it's most likely the rear.

Rotor warp can come from a piston hanging up and applying too much heat to one side of the rotor, especially if it's happening that quickly. Once you identify the problem, it may be good to inspect the caliper and other sliding surfaces

Also, build up and corrosion between the rotor and hub may be the cause of your repeated problem.

My course of action would be to identify which are pulsating, remove the rotors, have them resurfaced (or replace), check caliper and sliding surfaces, regrease pins etc..., clean hub to rotor mounting surface and reinstall with new pads.

Note that if your rotors were resurfaced vs replaced earlier, this may be why they are a problem as they continue to warp even though they have been flattened to make them true on the surface.

 

im suspecting a caliper issue

 

Rotors almost never actually warp. Usually it's uneven buildup of pad material on the rotor that causes what people think is warped rotors (pulsating).

 

True ^^

 

Get front wheels off ground, spin each wheel by hand, any unusual drag or hard to spin? Uneven wear on pads on either side? Do same on rear tires. Had same issue at 100k, front caliper piston was seizing up. Replaced both front calipers and rotors with OEM parts.problem solved. Hope this helps if you suspect a rotor,I always replace never resurface.