KM9V

I've got a brake problem that I can't figure out. My brakes were pulsing or wobbling. I replaced the rotors (which the brake guy said were warped) w/ cross drilled ones & new pads. But I still get some pulsing. My tires are balanced & rotated every 7500 mi. Here's the wierd thing, it doesn't happed all the time. It happens more when the brakes are hot/stop & go traffic. Hard braking doesn't pulse hardly at all. Could it be the master cylinder? Could there be air in the brake lines?

trackbird

iTrader: (4)

Could be a byproduct of the drilled rotors. But, it is more likley to be caused by pad build up around the holes in those rotors or on the surface of the disc. The buildup will cause uneven friction and if it is heavy enough, it can cause a slight pulsing of the pedal (the buildup makes the rotor thicker).

My thoughts.

KM9V

The pulsating started almost imediately after the new rotor & pad install. I just checked, the rotors look clean.

trackbird

iTrader: (4)

It only takes about .004 of an inch of pad build up to be noticeable during use (but very hard to see). I'm not sure a visual inspection would reveal the levels of build up we are talking about.

My thoughts.

trackbird

iTrader: (4)

I've seen brand new, warped, rotors. You may have a set that is warped from being stored vertically (standing on edge) or a manufacturing defect.

I worked at a parts store that stored rotors vertically (though we advised them to do otherwise). Most rotors that were there for any length of time and then sold, came back as "warped" when brand new. Just a thought.

mitchntx

iTrader: (14)

It's from the drilled rotors.

KM9V

How come it happens only when the brakes are warmed up or stop & go traffic? If the rotors were warped, wouldn't they pulsate ALL the time?

roy

heat exagerates the problem. it still there when cold but it is unrecognizable to your foot.