Is this an ABS sensor issue?

JeepManGood

JeepManGood

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Florence, SC
I’m going to take a flyer here and hopefully someone can point me in the right direction. My daughter has a 98 TJ. Had to put new wheel sensors on the front. ABS light went off and the first time it was driven it came right back on. Thought maybe I installed them wrong or the rust on the tone ring clipped it. Wire brushed the tone ring, installed two new sensors, spun the wheels to make sure nothing was hitting, light went off and everything seemed to be perfect. Drive two blocks and the ABS light came back on. Got back to the house, looked at the sensor and sure enough the passenger side front is broken again. Any ideas?
 
Thanks for the reply Jerry! There isn’t a mount necessarily. There are two holes on the steering knuckle. One is for the bolt that goes through the sensor and the other is for a plastic nub that is built into the sensor. As long as the nub is in the hole and the bolt is in, there is zero play in the the sensor and it maintains a fixed position, so there isn’t really a way to install it wrong and there is no adjustment for it. The sensor has a very small gap between it and the tone ring..... maybe 1/32 - 1/16. Although there are no obvious signs of wear, the only thing I can think is maybe the wheel bearing has a little play in it and it’s enough for the tone ring to clip the sensor. Just wanted to see if anyone here has experienced this and knows for sure. Again, thank you for your feedback and I will keep everyone posted. Hopefully I will get to the bottom and will be able to help someone else.
 
After you replaced the ABS sensor and spun the axle shaft the clearance was fine, but when you placed the Jeep on the ground with the full weight of the Jeep applied to axle; some of the clearance was removed. I think you are on the right track concerning the hub unit bearing.
You need to test your theory.
Measure the clearance while the tire is not touching the ground and after it's on the ground.
The hub bearing may be on its way out.
 
CharlesHS said:
After you replaced the ABS sensor and spun the axle shaft the clearance was fine, but when you placed the Jeep on the ground with the full weight of the Jeep applied to axle; some of the clearance was removed. I think you are on the right track concerning the hub unit bearing.
You need to test your theory.
Measure the clearance while the tire is not touching the ground and after it's on the ground.
The hub bearing may be on its way out.
Click to expand...
Thanks Charles! That’s exactly what it was! Now to find bearings with the tone ring attached!!!
 
I believe you can take the old tone rings off and put on the new axle. Use a torch to heat them up all around the circumference while trying to not heat the mass of the shat too much They should,then pop off with the slight pry of a screwdriver.
You install on the new shafts after cleaning up real good, then placing in an oven at about 350 degrees. Using tongs, remove from oven, and run out to where new shafts are already positioned to drop the ring onto, and have a hammer ready to tap the ring in place. It should fall right into position without the need for the hammer - the hammer needs to be there just in case.
Or you can buy new tone rings. Just be sure to get the right tooth count.
FWIW - rust doesn’t have any bearing on how well they work, as long as the rust isn’t deep penetrating rust that causes metal flaking.

I kinda sorta going thru the same thing on my ‘03 that I bought a 97 rear axle for. I forgot to look if it had ABS - and of course, it didn’t. Luckily I found some axles with tone rings on them for cheap (from what I can tell, ‘97 axles will not accept the tone ring, and in pulling one of the drums, the tone ring isn’t there).
I also found ABS backplates to replace the ones on the ‘97 axle.

My objective being, I want to be able to minimize downtime once I pull the old axle by not spending a bunch of time swapping parts.
 
Thanks for the info, I will give it a shot! Compared to doing the frame with safety caps on both sides it sounds like a walk in the park.
 
I have been having an ABS sensor issue too, replaced all four sensors and the light stays off most of the time and then occasionally comes on, usually at the end of a drive when driving slowly on the streets approaching my house or my destination. Do you think this could be a tone ring problem as well?
 
Honestly I’m not sure. I think that’s the problem on mine but I haven’t gotten new ones yet so I’m not sure. Scan it with an abs sensor and see what comes back. If it’s going on and off the scanner mightn’t catch it. I would check your connectors by unplugging them and looking in side for corrosion then plug them back in tight. Make sure the sensors are seated tightly and check your wheel bearings. Once I replace the bearings on mine I should know more. Could also be a bad sensor that’s going on and off intermittently too. You can also use a tester on them from the plug and test the continuity. If it beeps it’s good, if not it’s bad. Move the wire around when your testing it and see if it breaks continuity. Almost sounds like a bad connector.
 
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