1998 ford explorer front brakes act like they are sliding on ice.At the same time the anti lock brake pulsation is going on. I'm told that perhaps the front wheel sensors have gone bad and are in need of replacement.Is this the probablemand are thet located in the front bearing assemblies?

Usually this is a bad wheel bearing. Some times they make noise, sometimes not. You will have to put a scanner on it and find out which wheel sensor is acting up.

It means your anti lock brake system is no longer working. The good news is your brakes will still work, but if you slide on ice or snow your car may not continue in a straight line as it should with ABS. The reason your ABS stopped working is usually a sensor on the back side of the wheel has gone bad

Yes, you have one, but do you know for a fact that it's bad? All it does is control the brake bias between the front and rear wheels. If your rear brakes are locking up, other things that may cause it are a malfunctioning anti-lock brake system. A leaking axle seal will also cause the rear wheel to lock up when braking somewhat hard. If you're positive it's the valve, look by the brake booster under the hood. Follow the lines out of the booster and you should locate it. It's either right under it or next to it.

The "pulsating" you refer to is Normal for a vehicle with ABS (Anti-Lock Brake Systems). It keeps the vehicle braking in a straight line and monitors each wheel with a sensor as to how fast it's turning while braking. The "pulsations" you feel is the ABS Computer turning each individual brake on and off to prevent a lock-up or skid. Perhaps if you road test the vehicle and apply your brakes lightly as in coming up on a stop sign in a residential neighborhood, you'll feel what you consider to be, "normal braking." Pulsations usually come at higher speeds and as to how much pressure you're putting on the brake pedal. You're safer than most now knowing that braking, even in snow, rain or gravel, that your vehicle will stop in a straight line instead of sliding to one side or the other.

If unhappy with ABS Braking, you can always remove the fuse to the ABS computer rendering it inoperative, so you have both choices as to what you'd like to do, right here.

I hope this helps,

~00 Buck~

"Still Living on the Right Side of Dirt..."

if a speed sensor goes bad your ABS system will not function meaning your anti-locking brakes system, will not pulsate mulitple times if you step on the brake too hard or you hit a patch of ice, Most people hit the brakes hard when they start to slide across the road, however that allows the car to slide even more because the brakes are completely locked. The Speed sensor monitors the wheel and once it determines that the car is sliding it then kicks in and presses and releases the brake very fast and that is while you press the brake once.

Sounds like your Anti lock brake valve is not functioning right. The bad thing is that it has to be serviced by a technician. When they lock up is there any lights on the dash that light up like something that says anti-lock?

Anti-Lock Control —Vehicles Built After 03/2002 The 3-channel anti-lock brake system consists of the following components:

• front wheel speed sensors
• front wheel speed sensor rings
• hydraulic control unit (HCU)
• Anti-lock brake control module (ECU)
• rear wheel speed sensor
• rear wheel speed sensor rings
• yellow anti-lock brake warning indicator

The 4-channel anti-lock brake system with traction control and stability assist system consists of the following components:

• active brake booster with integral solenoid
• brake booster release switch
• front wheel speed sensors
• front wheel speed sensor rings
• hydraulic control unit (HCU)
• stability assist module (ECU)
• stability assist event indicator
• lateral accelerometer
• longitudinal accelerometer (4x4)
• rear wheel speed sensors
• rear wheel speed sensor rings
• steering wheel position sensor
• yaw rate sensor
• yellow anti-lock brake warning indicator
• brake pressure transducer
• traction control switch

---------------------------------------------------------------------
I suspect the abs issue is causing the speed control not to work if it happened at the same time the cruise control stopped working. When the yellow ABS light comes on, it means the ABS is dactivated. You may have a faulty accelerometer which senses acceleration and yaw (side to side lean). I have not seen a bad one but you said it is sensitive to acceleration.
I would unplug it and see what happens. The connector should have a small tab to depress so you can pull the connector out.
Here is where it is:

Accelerometer Removal and Installation

1. NOTE: The accelerometer is located under the center, rear passenger seat carpet. (I think you have to remove seat for access).
   Cut the carpeting along the perforations.

1. Disconnect the electrical connector.

1. Remove the nuts and remove the accelerometer.

Have dealer hook up tester and pull fault codes if you can't find an easy solution.
Some background info

A malfunction in the anti-lock brake system will cause the anti-lock brake control module to shut off or inhibit the system. However, normal power-assisted braking remains.

Malfunctions are indicated by the yellow ABS warning indicator in the instrument cluster.

The anti-lock brake system is self-monitoring. When the ignition switch is turned to the RUN position, the anti-lock brake control module will carry out a preliminary self-check on the anti-lock electrical system indicated by a three-second illumination of the yellow ABS warning indicator in the instrument cluster.

During vehicle operation, including normal and anti-lock braking, the anti-lock brake control module monitors all electrical anti-lock functions and some hydraulic operations.

Each time the vehicle is driven, as soon as vehicle speed reaches approximately 20 km/h (12mph), the anti-lock brake control module turns on the pump motor for approximately one-half second. At this time, a mechanical noise may be heard. This is a normal function of the self-check by the anti-lock brake control module.

Pedal pulsation coupled with noise while braking on loose gravel, bumps, wet or snowy roads is normal and indicates correct functioning of the anti-lock brake system.

Warning Lamp Indicator
The anti-lock brake system (ABS) uses the yellow ABS warning indicator to alert the driver of a malfunctions in the ABS.
The yellow ABS warning indicator will come on to warn the driver that the ABS has been turned off due to a symptom that exists in the ABS. Normal power assist braking remains but wheels can lock during a panic stop while the yellow ABS warning indicator is illuminated.

-----------------------------------------
Please report back, I am curious if that is what it is. Good luck

have you replaced front brakes 3+ times? normal wear is 3 front to 1 rear. plus ratio of braking for MOST veh's is 70% front vs 30% rear. rears could simply have worn out!

abs relay some times go bad

That is just the ABS system at work. It is supposed to prevent your wheels from locking which often makes the brake pulsate, especially in wet weather or or snow or ice. The only way to really stop this is to disable to ABS by unplugging it and removing the fuse. This will make the ABS light appear in your dash, but your brakes will stop pulsating.