Replaced Abs Wheel Speed Sensor

Stranger ranger · October 19, 2011

Long story short, I was rotating my tires and checking my brakes on my 06 HD. My pedal, since I bought the truck, would pulsate very little intermittently coming to a stop right around 3 mph. Never bothered me and heard the sensor just gets dirty and needs a good wipe off. Took the passenger side apart, pulled the sensor out and bam, it was caked with crap. Cleaned it off, put everything back together and moved to the driver side. After I ruined the rotor trying to get it off I cracked the case that the metal sensor is in on the abs sensor trying to get it out, it was dirty too so I cleaned and replaced in hopes it would still work. Replaced junk rotor for the time being and went for a spin and the issue was no worse, but no better. So I thought to myself, just pick up a new sensor tomorrow when you grab a rotor. Easy enough right? Well last night i changed the rotor and sensor and to my dismay, I went for a drive and now my ABS light comes on periodically and the pulsation is 10 times worse than what it was. Its so bad that you actually need to pay attention or you'll rear end someone so you better be ready.

I had the key on all the way forward so I could listen to radio and turn the wheel as needed to remove the caliper bolts with the air gun so I'm not sure if this has anything to do with it or not. Also, I've read about there being a bad ground BUT, with zero issues (forget about the very minor pulsation I had since i've owned the truck) before I replaced this sensor with a brand new one (unless they are reman and I happened to get a junk one) why would it all of a sudden be the ground? Should I replace the passenger side and see where I stand? Take the driver side back and get another?

I gotta go on a tow very soon and i'd really like for my brakes to be working properly. It just kills me that it was fine before I messed with it and now its already cost me 100 spot.

Debo511 · October 19, 2011

Remove both front WSS's and use clean the mounting surface , preferably with a die grider and sanding disc, Sand down to bare metal, apply some corrosion protection and re-install the WSS's

Stranger ranger · October 19, 2011

Remove both front WSS's and use clean the mounting surface , preferably with a die grider and sanding disc, Sand down to bare metal, apply some corrosion protection and re-install the WSS's

So you're saying the outer portion of the hub assembly, top of the screw and sensor holes, needs to be cleaned to bare metal? This would makes sense I guess because mine are both rusted and corroded up. Does the sensor use that as a ground?

asc08 · October 19, 2011

No, the surface rust on the bearing where the sensor mounts will actually push the sensor slightly away from the 'gear' inside the bearing, and give you a false reading.

Before you put the disc back on, take a digital volt meter and connect it to the leads coming off the sensor. Give the hub a good spin by hand. You should get a reading of 350 mV DC (.350 volts).

Be sure you do as DEBO says and clean the surface under the sensor down to bare metal, and add some corrosion protection.

Stranger ranger · October 19, 2011

hmm. i took a wire brush to it but i'll have to clean it more i guess. I removed all the flaking but I probably need to remove more.

asc08 · October 19, 2011

hmm. i took a wire brush to it but i'll have to clean it more i guess. I removed all the flaking but I probably need to remove more.

I went thru the exact same thing. Used a wire brush, thought I did a good job, but had the problem, but after I made my first attempt, it was worse, and the ABS light was coming on. ABS light never came on when the problem started, only the low speed ABS activation. Check the voltage if you have a meter, and if it is 350 mV or greater, you are golden.

Stranger ranger · October 19, 2011

and if not, junk sensor?

what did you use just a wire wheel on a grider or flap disc?

ChevyTech77 · October 19, 2011

A straight die grinder with a deburring bit using light pressure works best to clean them.

Stranger ranger · October 19, 2011

ahhh, i have just the tool for this i think..

I'm hoping this works. i'll keep everyone posted.

Stranger ranger · October 20, 2011

Well I took both sensors off tonight and cleaned their mounting surfaces and reinstalled everything and now it works perfect. Hard to believe that a little bit of rust caused all that hassle. Thanks guys.

ujtruck · October 20, 2011

Good to see, its working and thanks for updating - pretty sure this will help someone

Stranger ranger · October 20, 2011

I really didn't even need to replace the broken sensor, it was still working fine just needed the surface cleaned but screw it.

Rons05z71 · October 21, 2011

I didnt think you could replace those without doing the entire hub assembly

Stranger ranger · October 21, 2011

Me neither, until I looked online at advance autos site.

iamtron · October 24, 2011

I replaced the WSS on my 2001 Silverado when they got so bad, that the abs wouldn't let the truck stop. Parts store told me I couldn't just replace the sensor and I had to do the whole hub. But went to the dealer and they sold me just the sensors. As you found out the key is the distance when the sensor is installed, so make sure you get all the rust knocked down. Just be carefull not to get junk in the hole for the sensor while grinding it down.