My wifes 2000 Explorer started this problem about last July. She came home one day and told me that when she makes a braking left turn, the pedal goes down. I take it out and couldn't get it to do it.

So lately she says its doing it going straight when she brakes, except that the pedal goes to the floor. It does stop, but it scares her when the pedal goes to the floor. I told her to let the pedal up and push again. When she does this, she gets a full pedal and it stops as it should.

Today, I took her to work so I can take a closer look at it. I called a friend that was ASE certified a few years back. He ruled out the booster, master cylinder, brake line leaks, and wheel cylinders. We both went to an empty parking lot and sure enough, when making a braking left turn, you can feel the pedal pulsate and go towards the floor with each pulse.

We hooked an ohm meter up to the leads going to the sensors for the front wheels. Spun the wheels and the meter would pulse as they turned.

Rotors and pads are new 2 months ago. Semi-metalic with lifetime rotors.

Any ideas? Can codes be pulled to show what and where the problem is? BTW, the ABS light comes on during the self test when the key is first turned on, but goes out afterwards. No other lights are on. Thanks DNB

 

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I'm sorry, yes I should have also mentioned that the reservoir is full, and all air has been bled out. Brake pedal is normal, braking is normal most of the time. This problem is only intermittent. The only time the pedal goes to the floor is when the ABS seems to kick in. You not only feel the pedal pulse under your foot, you can hear the clicking noise it makes as well. All braking is good until the ABS system kicks in for no reason. This does seem to only happen at speeds under 20.

 

Bleeding the brakes the conventional way will not bleed air from the ABS pump. Even with that being the case though, if there were air in the ABS pump, that air would be introduced in to the brake lines when the ABS engaged, so over time you would end up with air in the lines and a soft pedal during normal braking.

This is an interesting one. Since your ABS light is not coming on during the self test or, presumably, when the ABS is engaging on left turns, checking for ABS codes may not tell you anything. However, if you were to connect a professional scan tool that can monitor the ABS system parameters real time during a left turn, you may be able to spot a sensor or signal that is not behaving the way it should which could point you in the direction to focus. Without that information you're kind of stuck looking for a loose wheel bearing or an ABS sensor wire that is getting stretched during a left hand turn.

If you take the vehicle out on a gravel or sand road and get the ABS to kick in while going straight do you still have the sense of lost brakes?

I've run in to front ABS sensor wiring on a few GMs (a couple of Malibus and a Venture) that seemed too short and not well sealed from the elements. When it was wet outside the ABS would engage as the cars were coming to a stop well before it was slow enough any of the wheels were locking up. On the scan tool I could watch the wheel speeds count down, and on all three it were the passenger front. It would get to about 7 mph then drop to 0 mph. I ended up needing to replace about 18 inches of wire between the sensor connector and the body of the car due to a loose connection and corrosion. I had to go back 18 inches to find clean enough copper to solder to.

-Rod

 

I called my local shop and asked if they had the scanner for checking the ABS. He said they did. I dropped the Explorer off that evening. Yesterday he calls and said that the left front hub was the problem. Had his garage change it out. We took it back out afterwards with the scanner and it showed that everything is back the way it should.

At low speeds, the sensor ring in the hub became erratic causing the ABS to kick in. Wife is happy now and so is everyone around her.....

Thanks for the help,,,it is appreciated very much.

 

Awesome, glad it's fixed! And thank you for following up with what you found to be the issue.

-Rod