2000 silverado Z71 brakes

[dakota1205]

I been noticing when I brake on my 2000 Z71 Silverado, I would feel the ABS brake system working (brake pedal would feel like it was all way down and feel the ABS working so the tires would not lock up).
So I got noticing my brakes and rotors. My rear brake rotors were bad shape (rusty, metal flaking off them, not able to be turned). I have replaced front brakes pads and rotors, rear brake pads, rotors, and calipers, blead all lines (went through 1 quart of fluid, to replace old fluid).

So why am I still having braking issues? Any insight would be helpfull.

[Airjer_]

Do you notice it more at slow speeds?

If so you have a speed sensor dropping out (most likely cause anyways). It has nothing to do with the brakes themselves. This can be confirmed with a scan tool. One the suspected sensor is located the sensor should be removed from the hub, the hub surface cleaned, a small amount of grease applied to mounting surface and then reinstall the sensor. This is covered in a TSB for this problem for this and other GM's with similar setups.

[j cAT]

Originally Posted by dakota1205

I been noticing when I brake on my 2000 Z71 Silverado, I would feel the ABS brake system working (brake pedal would feel like it was all way down and feel the ABS working so the tires would not lock up).
So I got noticing my brakes and rotors. My rear brake rotors were bad shape (rusty, metal flaking off them, not able to be turned). I have replaced front brakes pads and rotors, rear brake pads, rotors, and calipers, blead all lines (went through 1 quart of fluid, to replace old fluid).

So why am I still having braking issues? Any insight would be helpfull.

as mentioned this is a well known vehicle defect . the ABS sensors on the front hub bearing have rust that pushes the sensor out of its position there by reducing the sensor voltage to the computer..

ABS comes on only at very slow speeds/no braking at 5mph speed.

the other componet is the hub bearing is failing.
what happens here is rust from the bearing coming apart fouls the sensor pick up surface. this causes ABS to always come on reducing braking..

the bearing may not look/feel bad ...the rust is what gives it away. remove the front rotors, remove the sensor need allen wrench . spray sensor with rust buster spray. carefully rotate sensor while you pull out of hole not too much force.grease should look clean if rusted or particles replace hub...

testing these sensors is easy. with a voltmeter on ac volts the sensor when you rotate the hub should put out at least 380millivolts or .38 volts AC. A new hub bearing will product 500MV or .5 volts plus...

I get these hubs from 1A auto as they have the best prices..hubs made in taiwan..less than 100.oo...sensor included..

[dakota1205]

When I replaced the front brakes and rotors, which was ~6 months earlier, I read about the sensors, I did pull each one out and looked at them, they both appeared to be shiny on the sensor and looking down inside the hub, you could see the shinyness of the hub with looked like little grooves around the hub. Did not appear to have any rust inside. But I will say this, my front rotors was in pretty bad shape, (rusted) that 3 different places say they were not turnable. So I had to buy new ones. So if this being the case, would my hubs be bad also consirdering the condition of my rotors and I just can't tell it.

Thanks for the Info guys!!!!

[Airjer_]

The hub is the part that has the studs. The bearing is the part the hub fits into. Its the bearing that would be bad but they are sold as a bearing/hub assembly. It is possible for a bearing to be bad but not bad enough to show any signs.

Like I said this is a 20 minute diag with a good scan tool. Once you figure out what wheel is dropping out signal you can focus your attention there.

[j cAT]

Originally Posted by dakota1205

When I replaced the front brakes and rotors, which was ~6 months earlier, I read about the sensors, I did pull each one out and looked at them, they both appeared to be shiny on the sensor and looking down inside the hub, you could see the shinyness of the hub with looked like little grooves around the hub. Did not appear to have any rust inside. But I will say this, my front rotors was in pretty bad shape, (rusted) that 3 different places say they were not turnable. So I had to buy new ones. So if this being the case, would my hubs be bad also consirdering the condition of my rotors and I just can't tell it.

Thanks for the Info guys!!!!

I forgot to mention the wires and fasteners that secure these ABS sensor cables need to be checked ..problems of the rotor wearing into the cable is also common..

all you need to check is the voltage as I earlier described ..
just remove tire , disconnect the sensor connector hook up ac voltmeter and spin hub ..