Apparently the cause of the noise I was hearing was the ABS sensor coming in contact with the sensor ring. I can see the light scrape marks on one side of the exciter ring of the original rotor.

I don't see any apparent damage in the area, so I figured I would remove it and check things out.

How the heck do you get the ABS sensor out? I removed the bolt from the rear, but it resists all moderate attempts to budge it?

Didn't want to just wail away on it...

 

Ok, apparently there's a second bolt holding the sensor...

 

Been doing even more digging, and found some old usenet posts where people talked about the exact problem... Sounds like it may be bearing related...

One talked about having to slightly shim the wheel speed sensor to allow additional clearance. Thats what I wanted to do except I can't get the dang sensor out..

Thinking about swapping the rotor from the other side in to see if I still have the problem...

 

So how is the wheel bearing play????

Maybe all thats needed is a wheel bearing adjustment, or maybe you have a warped rotor, whats it's runout, with the wheel bearing adjusted to spec???!!!!

 

Here's the story so far -

Just got this truck, had noise I really thought was wheel bearing. Set out to replace bearings and seal on both sides.

Left side, no problem done.

Right side, I found the inner race was turning freely, it literally fell out with the slightest tap. I decided that I had best replace the rotor.

I got a new rotor, which of course came with races pre installed. Put in my new bearings and seal, and fit it up.

Manual says to tighten to 35 ft/lbs initially while turning rotor. The rotor locks up tight due to the sensor contacting the ring on the hub.

Inspecting the old rotor shows that there was contact on slightly less than half of the ring, which is probably where the noise was coming from.

I don't know any further history of the truck, so I can't say if there was accident damage or anything...

I was thinking about swapping the rotor from the other side to see if there was still a problem. Or that possibly it was the rotor I bought. Thinking more about it, that doesn't explain why there was contact on the old rotor.

 

I was talking to someone today who mentioned the steering knuckle might be damaged... How would I determine that?

 

Is the bolt that holds the wheel sensor a spline head? If so, what size?

 

Well maybe the wheel spindle got messed up, on the the rotor that had the loose race.

Is your replacement rotor a OEM Motorcraft, or aftermrket????

 

Those sensors tend to rust in place pretty good... sometimes the only way to get them out is to break them.

Buy a new sensor... tap the old one out (it'll break upon removal)... use a wire brush to clean up all the rust in and around the mounting hole (over time the rust deforms and pushes out the sensor... causing it to hit against the ring).. install new sensor and you should be good to go.

Unless.. the rotor is incorrect or something.. which does happen once in awhile.

Good luck

 

Rust problem deforming the sensor sounds plausible - could very well be the issue - lot of rust on the underside of this truck...

Anyway, I can remove the bolt that holds the sensor wire in place, still have to contend with the second bolt behind and to the side of the sensor. Nothing in the manuals say anything about what type of fastener it is. I'm thinking it's a splined head bolt... of course I don't own any splined sockets...


Thanks very much for that info!

 

I went and picked up a replacement sensor today from the stealership. As soon as I saw the new sensor, I realized that there was only the one bolt, and that the manual just hadn't been real clear. There was a cable clamp a few inches up the wire, and just the one bolt that holds the sensor in. The bolt next to the sensor doesn't get touched.

So with that knowledge, I realized I was going to have to wail away on it...

MazdaRangerGuyInSTL was right on the money about the sensor rusting in place - it came out in pieces. The guts came out of the outer metal can. That can was REALLY stuck in there - took 20 minutes of careful chiseling, etc. After the hole was clear and all the rust cleaned out, I installed the new sensor, new rotor & bearings, and snugged up the bearing adjusting nut.

So, what happens? - the sensor is rubbing the tone ring again!. Obviously something is out of spec on that side. Bent spindle? I sure don't know..

I used a small shim on the sensor, and got enough clearance. It really didn't need much - I shimmed it with a washer between the sensor and the mounting surface, maybe 1.5 mm thick. Put it all together, and tried it out - No noise, the ABS controller seems happy with the sensor.

Only thing I heard was tire noise...

Thanks for the tips!!!