khardin1

First post, sorry need help.
OK, replaced front rotors and pads. Also replaced rear pads. Went for a test drive. It sounds like a grinding and bumping, pulsing in the pedal, kind of from the front driver side. After about 3 to 5 good stops, the ABS light comes on but then the noise and all stops. After the light comes on the brakes work like a new truck. If I shut the truck down it restarts this series of garbage; bad breaking until the ABS light comes on and then the brakes work great. I tried to bleed all 4 two different times. Took the tires back off and checked; everything looks fine. What could this be guys? I plan to drive to work tomorrow. Please give me some thoughts. Thanks!!!

khardin1

did I stump you guys that bad with this problem? Surely someone has had a similar problem. Thx

3wV

Sounds like the grinding is you took out an ABS pickup tone unit or the tone wheel was scraping on the unit, the noise went away cause it was shaved down, the ABS defaults to a redundant in the ECU are good to go is like new in the backup or fail-safe mode.

So, check the tone wheel from the noisy side you were hearing it from.

khardin1

What is the tone wheel? Is that the thing that looks like a big gear on the inside? The grinding happens everytime I start out and then goes away once the light comes on. I dont think it is actually anything grinding though.

3wV

It looks like a ring with uniform cuts all around the ends. This counts 360° and if a wheel say stops at 180° on ice and the tone wheel stops? The tire skids for that ever so nanosecond, the ECU calls the wheel servo to unload the hose with fluid is let it roll.

So, if you remove the wheel, remove the brake disc, look for a tone wheel that is peppered with filings or say the reader or the tone sensor that is that static little black thing you see it is going to tone a magnetic wave over that gap and that is the reader is if it stops, you know the rest of the action jackson.