My 2WD '05 has about 60K miles. The front brakes were pulsing, so I replaced the rotors and pads today. Now the pedal is soft and the ABS warning light is on. Does this mean air got in the lines when I pushed the pistons back into the calipers? There weren't any leaks, nothing wet before or after the work. I used Bosch QuietCast rotors and EBC Green Stuff brake pads. Everything went together perfectly. The ABS light is on from startup, before the truck is even rolling. Other than the soft pedal, it steers and brakes normally (no pulling or grabbing). Any help with this will be appreciated!

 

There's a tone ring on the hub. Did you double check to make sure they aren't damaged before installing? That happened to me a few years back. If not, it may be sensor related. I would try bleeding the brakes as well and make sure you did not damage the piston on the caliper.

 

Well, I drove the truck an hour ago after it sat most of the afternoon. For some reason, the brakes don't feel so bad now. Maybe it was just because the pads were new, adding to the somewhat soft characteristics of the Ford pedal. Anyway, it seems like I should concentrate on the ABS problem for now.

If something was wrong with the tone ring on the hub, would it cause the ABS light to come on even before the truck starts moving?

 

i had my light come on and wiped off the sensor that hovers over that ring on the rotor. my light went off after that.

 

Yes, you need to check the sensors. You may have damaged one or knocked one loose when you were doing the brake job.

 

I had the codes read yesterday after work. No go at O'Reilly's, AutoZone and NAPA, but Advance Auto was able to do it. The scanner said there's a fault in the RF speed sensor. Nothing out of the ordinary happened during this job, so I suspect wire fatigue in the sensor cable. I'll buy a new sensor and inspect everything this weekend. If I'm lucky, the sensor can be replaced without pulling anything more than the wheel. Thanks for everyone's input on this!

 

FYI, Autozone has a scanner in their free tool rental program that is capable of viewing and clearing ABS fault codes. It's the Innova 3150. The staff is generally pretty ignorant about it, but if you ask for that specific scanner, it'll get the job done. I think the "price" was $240, which was obviously refunded when I brought it back.

http://www.autozone.com/test-scan-an...bs/273347_0_0/

 

Good to know, thanks!

 

Glad you're getting somewhere with it. Be sure to post back your results.

 

I am not sure about these trucks, but I had the ABS light come on in my wife's 05 Escape. After a little on-line research, I discovered it was a busted tone ring. It was still in place on the hub, but I could take my finger and spin it. You can see the crack in the pic. I was able to replace it myself for ~$15. Good luck!

 

Now I'm stumped. I picked up a new BWD sensor (ABS1027), but it didn't fix the problem. Start the truck, put on the seat belt, and all the warning lights go out except ABS. Why would the scanner report a fault in the Right Front wheel speed sensor if the problem isn't actually the sensor? Is it possible the new sensor is bad? The box did look kinda grubby, and it had been opened. Is there a way to test these sensors with test equipment? I have a workbench with a lot of equipment - variable power supplies, voltmeter, o'scope etc.

 

I've seen sites that actually list the ohms and I believe it is different for 2wd vs 4x4 but it sounds as though you're good on passenger side and dead on drivers. These things will have an acceptable range of ohms across the 2 wires on the sensor. Unplug both and measure the resistance across the 2 wires with a good digital meter. If both are around the same, and especially if the old one is about the same too, then it wasn't a sensor in the first place. Don't know the Ford but if it's the same as others I have worked on, these sensors are more like mini generators generating a small electrical pulse each time a high spot on the ring passes it. This pulse is measured by the ABS computer. It wouldn't put out voltage from the computer to the sensors so probably no way to measure there.. Also, expect it's the same as GM and on GM if the computer "sees" the sensor, then no ABS light on start but if it fails to read the wheel moving, ABS comes on once you start to move. If it doesn't see the sensor at all, ABS light comes on just running without having to move.

If your light comes on with engine start, the circuit to, or the sensor itself is open.. If it's OK until your drive a bit then it's misaligned (too far from ring etc) or the ring is broken.. Did you have to sledge hammer the old rotors to get them off or anything? Did you leave the caliper hanging by the hose/wire combo?

 

Forgot to ask, did you drive the truck after swapping sensors? It may need to see a wheel output before it clears the light too.

 

Yep, that was it!! I drove the truck a few miles this evening, and the light went off. Wasn't expecting it to do that. Man, I'm glad she's fixed! Now I can replace the rotors in the back!

 

Just wanted to follow up on your questions. Thanks for describing the operation of these sensors. I did use a sledge hammer on this job, but it was on the left front rotor, not the right side where the bad sensor was located. On that side, I was able to pry the rotor loose without much force. Whenever I work on disc brakes, I place a large block of wood about a foot high next to the wheel. I set the caliper on that when it's loose, just to be sure the hoses/wires don't get stressed. I've gone over the work I did on this truck several times in my mind, trying to figure out what I might have done wrong. There just isn't anything I can think of that could have caused this failure. I can only guess it was a combination of wire fatigue and bad luck.

I finished up the brake job today with new rotors and pads on the rear. The Bosch rotors and EBC pads are working really well together. All the pulsing is gone, and braking is smooth and quiet. I'm hoping this is the last time I'll need to pull a caliper for at least another 60K miles.