Abs Question

[nicecar]

Hello everyone, here is something strange happening to my 96 es300, the ABS will kick in while braking on dry pavement right before the car comes to a complete stop, especially when braking at a corner while turning the steering a little, I can hear the clicking from one of the front wheels and can feel that clicking with my foot stepping on the brake paddle, tires and brake pads are good and my local mechanic could not find out what’s causing it. Any advice is appreciated.

[gbhrps]

You don't say whether your local mechanic is a Lexus Technician, and I suspect not. I'd say that all he did was pull the wheels to check the brake pads and rotors and nothing more. He didn't pull the rotors to look at the speed sensor rings attached to the wheel hubs, I'd be willing to wager. Behind all of the rotors is a heavy toothed metal ring, much like a gear with square teeth. It turns with the hub and wheel. Attached to the strut is a sensor that is aimed at the gear and measures how fast the geared teeth are passing by. This happens at each wheel and the data is compared at the ABS computer. If it notices that one or more wheels is out of synch with the others, on goes the ABS. I would think that if you pulled all 4 rotors you would find that one of the rings is loose and needs tightening, the rings are rusty or corroded and need cleaning to true the system up, or one of your sensors is gummed up, loose or defective. Then again your ABS computer may be on the fritz. Some of this is a DIY, if you are handy and careful, and some is definately better left to the Lexus boys. Good Luck and hope this has been of some help.

[steviej]

this happens sometime upon first depression of the brake pedal when I am leaving the hospital parking garage. It only happens once when I hit the brakes and when the car is on a decline ramp. But then I can't get it to do it again after that. I just assumed it has something to do with the surface oxidation on the rotors making the braking send mixed messages to the ABS ECU.

Haven't had any problems or quirks with the brakes other than that scenario.

steviej

[SKperformance]

normal wear will cause a wheel hub to need replacing.

the extra play in there cn cause the cv joint to move away which is where the sensor is attached to .

the sensor which is basically a magnetic pick up will never get loose as it is squeezed into the wheel hub and usually gets destoryed if removing it to replace it in a new hub assembly.

The cv joint is physically imprinted with the metal teeth so it neither can become loose .

I would say on an incline you would get the abs to kick on occasionally especially if it is treated concerate. It will build up on the wheels and slight slippage on the inside wheel of the corner will make the car think it is slipping especially if on a turn downwards.