98 Windstar ABS light on/ help

[bcramer1]

OK, while driving vehicle at most speeds above 10mph or so...when you apply brakes to slow down as in a normal stop, you can hear and feel the ABS system pulsating the pedal and the pedal goes down some. First start of the day, the light is off. After 2 or so braking applications that has the pulses, the light comes on and stays on. No codes present. Any help is appreciated, Bruce

[philkb]

You may have a wheel sensor that is going bad, but still has partial function, and it gets worse with heat buildup from normal driving. As for codes, only the special mechanic's scanner will pull them and they will not turn on your CEL. The ABS light is the sign that there is a problem.

[tripletdaddy]

A bad sensor does sound like a possiblity, though I don't expect them to get that particularly hot to be a factor due to their distance from the brakes and the steady air moving over them. Did the pulsating brakes begin before your abs light came on or did the two occur at the same time? Are you sure that the pulsating is not caused by a warped rotor? Did the pulsation come on all of a sudden or gradually? Does it really pulsate like in a wheel slipping braking situation? Do the abs brakes work as they should now on a slick surface? As rediculous as this may sound, on mine, I had just the abs light come on. I found nothing wrong on visual inspection and connections were tight. Surely the abs light wouldn't come on for low brake fluid level. That would be the job of the brake warning light. Well, the brake fluid reservoir was within normal operating level. Topping it off to its max level turned the light off!?! Unfortunately, I don't see how that addresses your pulsating brakes. I guess the moral is anything wacky goes.

[bcramer1]

Well the heat is not in question as the first time can be the the first stop you apply brakes. Rotors are true. Light comes on just after the pulsating occurs 2-3 times. So yes, they do occur at the same time. Sometimes the brakes work with no pulsing. 50-50. Cant seem to make it do it. been raining here, no garage so hopefully this pm I can get under the van and check connections and teeth on the ring gear. And I will check fluid level also! Did not try on a slick surface. yet.

[wiswind]

It is my understanding that once the ABS light is lit, that the ABS system is disabled.
Someone correct me if I am wrong.

If this is the case, any pulsing that you feel after the ABS light is lit, would not be from the ABS system.

It is very easy for the brake rotors to develop a slight warpage. Water hitting them when they are hot, uneven torque on the lug nuts, or a dragging brake pad.
The calipers can stick when they get old, or the caliper can stick on the pins that it is supposed to "float" on.

Another thing that can happen, is the gap between the pick up (sensor) and the gear (exciter ring) can become too great or too little.

A visual inspection of this would be a good idea.
You would need to pull each wheel, and inspect.
Spray down the exciter ring and pickup liberaly with brake cleaner.
I can see how metalic brake linings might cause an issue as the dust builds up on the exciter ring.

Do you need a brake job?
Have you had a brake job recently (a likely time for a pick up to have been bumped)?

Inspect the disk brake pads for uneven wear......more wear on the pad on one side of the rotor than the other side's pad would indicate a possible sticking on the slider pins.

If 1 side of the vehicle has pads that are worn more than the other side, then that caliper might be sticking, or the rotor may be slightly out of true.
Or maybe the brakes are just grabbing more on that side of the vehicle, although one would expect that the vehicle would pull to one side, if that were the case.

These "sticking" issues can be intermittent, so looking at the pads is a good way of tracking it down.

For sticking pins, I would replace and lub the pins with high temperature disk brake lube.
For sticking calipers, I would replace the caliper.....and they should be replaced as a pair (both sides).

If you don't find anything with your visual inspection, it might be worth having the brake codes read to get you down to the wheel and component that is causing the concern.
Hopefully, you have not developed play in a component (like a wheel bearing) that is causing the issue.

I am a big fan of getting a hardware "kit" when doing a brake job.
Particularly for rear drum brakes.
I have posted pictures of what is included in a brake "kit" for front disk brakes, and for rear drum brakes.
The caliper "pins" are bought separately, not included in the disk brake hardware kit.

[bcramer1]

It is definitely the ABS system as I can hear and feel the pump working to relieve the pressure on wichever wheel is malfunctioning. Rain is upon me again, so I just might have to wait till tomorrow. Brakes have half pad left (all pads). I want to disconnect ABS fuse and see what happens. Pouring out right now so that must wait for a while. Will post.

[bcramer1]

Heres one for you. I got out between raindrops, jacked the front left up, lo and behold what do I see? The speed sensor ring gear cracked and cockeyed on the axle. So what does one do in the darkening hrs in the mist? I realigned the ring gear back to where it was according to the marks where it was originaly pressed to and epoxied the crack to hold it from seperating at high speed and put some on both sides in several spots along the ring to keep it in place. I figured the epoxy is non magnetic so it wont interfere with the reading, and as long as she keeps it under 100mph it should be good for another 154000 miles.

[bcramer1]

Update, light came back on Can the other side be broke also? Dark now, tomorrow is another day.

[tripletdaddy]

Good find. But I'm afraid to tell you probably have to replace that cracked ring. Here's my theory why. (A) It is quite possible that the abs can detect that during non braking conditions, where the wheel spins smoothly it can tell the sensor is detecting a flaw in the excitor ring. Basically, it tests to be sure the system is ok. and/or (B) The abs still thinks your wheel is not moving smoothly because the sensor is detecting the imperfection in the excitor ring. Any detectable difference between each of those teeth will indicate to it that the wheel is slipping while braking when its not. The abs will keep trying to brake and release over and over trying to overcome the "slipping" condition created by the broken ring. When the abs figures out that it can't overcome the situation, it becomes "confused" and then throws the light on, thinking that there must be something wrong. It knows something is wrong, but without knowing what the code is or even if there is a specific code for this it still leaves you without knowing why the light has come on.

[bcramer1]

Yes, I see your point. Sounds like a very plausible fault in my thinking. There was a 1/8" gap I didnt close before I epoxied it which could be causing this.
Hows this? The ring must be steel to excite sensor. If I close the gap and hit it with my mig welder and grind to original dimension, think that would help? Van will be for sale in spring, and the wife only works 4 miles from home. I was just hopeing for an inexpensive fix for now, van does have 154K miles and needs other work. Can I pull the relay to knock the system out? Does anyone know which relay or where it is. My Haynes manual has all elec diagrams but the ABS. Eng compartment fuse center is not marked.
Oh, I forgot to mention, all brake pedal pulsing has ceased. Seems I have gained "something"

[tripletdaddy]

I like the idea of spot welding it back in place. Two thoughts, you need to be able to hold and weld it perfectly in place, in line and teeth pefectly spaced at the breaks and you may need to keep the cvjoint housing cool enough so you don't cook the grease inside. Ssuggestions are use a very large hose clamp to hold the gear in place and use a water soaked rag around the cvjoint on the boot side and maybe the wheel side if you think it will get too hot.
Good luck

[lapin_windstar]

This may or may not be helpful: when I bought my Windstar, I was told the ABS was "broken and disabled". The speed sensor ring was shot. A year later, I went through the fuse box and replaced all the dead fuses.

Without thinking it through, I replaced the "missing" (i.e. deliberately removed) ABS fuse. The next time I touched the brakes, they shuddered as if they were ABS pulsing but also with really bent, grindy rotors. I removed the ABS fuse, disabled the ABS and went back to my ABS-less existence.

All this sounds very similar to your experience - but I am not an expert or a mechanic.

[bcramer1]

My fuses arent marked, do you remember which fuse it was? The epoxy is holding so good, I am afraid that if I try to break it loose again, I will crack the ring further. The space the crack opened is 1/8" I am tempted to put a small piece of metal there instead of welding the ring. But at least the pulsing is gone. Just looks bad if I sell it though.

[tripletdaddy]

Did the abs light go off? Do you really trust and think the epoxy is strong enough to hold? The rotational forces involed can be surprising high and you'd be very regretful if it came off and is lost. I would trust a weld more. I understand your hesitancy to pull it apart to put it back together, but your welder is good for that. I'm not convinced you need to stick a piece of steel in the gap as the teeth and the air between them are what the sensor senses. The bottom of the ring is out the sensor's range. If you don't want to mess with it any more than you have to, I'd not mess with your epoxy.

[Captv2k]

On mines I had to pull out the fuse for the abs and it works fine. Try it I maybe wrong. Thank you.