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Thread: DIY: How to remove a stuck front ABS sensor

  1. #1
    Join Date
    Aug 2003
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    E30(sold *3), E36, E46

    DIY: How to remove a stuck front ABS sensor

    They said it couldn't be done! Everyone said that stuck ABS sensors in cold climate BMWs need to be drilled out, including experienced mechanics. I had to drill it out on a E30 once and it was time consuming and I'm not the destructive type. I wanted to see if I could get away with not doing this on the E36.

    Well, there's a way to get them out after all without drilling

    Tools:
    2 curved jaw locking pliers, one of them small. I got the set from Harbor Freight
    PB Blaster
    Small Butane torch (optional)





    Step 1: Remove Wheel
    Step 2: Remove brake assembly (2 large bolts). Do not leave this hanging! Support with coat hanger, etc.
    Step 3: Turn steering wheel to the opposite side to the wheel you are working on, for better access.
    Step 4: Remove disc rotor hex bolt.
    Step 5: Remove rotor (this might take some effort, as it can get rusted on pretty good. Prepare to hammer it off gently with mallet)
    Step 6: Remove ABS sensor hex bolt. These generally do not seize from my experience but be careful with it. Use some PB blaster and soak if nervous.
    Step 7: You can actually see that the ABS sensor goes through the housing and have access to a large part of it on both sides. Use PB blaster and soak it from both ends. I only soaked it for like 15-20 minutes.
    Step 8: Optional: torch the wheel housing. Note that this may melt some of the ABS sensor if you're not careful and/or break it.

    This is the useful bit:
    Step 9: Use the small locking plier on that part that is exposed between the wheel housing and the wheel bearing hub. It should just fit using the small HF one or similar. Use the medium size locking plier on the other end.
    Step 10: Rock both locking pliers back and forth. It should start moving with a little effort. Keep doing this until it's loose enough to pull out. Add more PB Blaster as required.

    Previously I had tried removing this using all other means including just one locking plier on back and the thing would not budge at all. I tried hammering it , prying it, etc. This was soooo much easier.

    Installation is reverse. Prepare to spend a lot of time sanding down the hole if you have a new sensor or used replacement in good condition. I ended up using sandpaper and filing tool and metal brush. Mini dremel would have been really handy.

    ABS/ASC light finally off. woohoo!!
    Last edited by bmwsmurf; 06-26-2011 at 09:02 PM.

  2. #2
    Join Date
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    Thank you, thank you, thank you! haha.

    I already broke one of these things and it was a PITA. I will try this tonight.

  3. #3
    Join Date
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    Maine, USA
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    1998 318ti 2001 330ci
    Thanks for this writeup.

    The first time I changed an ABS sensor, I used plenty of KROIL, clamped on the Vise-Grips, twisted and twisted, from the outside only, thought I was getting it loose, and ended up breaking off the outside portion of the sensor.
    After that I had a bright idea and used a hacksaw blade to cut off the inside of the sensor, but the part that goes through the steering knuckle was still stuck in there.
    I had to remove the wheel bearing / hub in order to get clear access to the sensor hole, then I tried to pound the piece out with a ⅜" extension, but all that did was to make a ½" hole in the middle of it, so I had to finally pound it out with a socket the exact size of the hole and a BFH.

    Not wanting to repeat that, especially on an 18° day, I was glad to have found your simple piece of advice.

    I removed the wheel, caliper (to get access to the caliper bracket bolt that is partially blocked by the brake hose), caliper bracket, rotor screw, rotor, and the three little screws that hold the sheet metal shield assembly to the steering knuckle, to mobilize it a bit for clearance.
    I sprayed both ends with KROIL like there was no tomorrow, snapped two pairs of Vise-Grips on the two ends of the sensor, and started tugging back and forth in unison.
    I will note here that it is MUCH easier to do ALL of this if the front wheels are turned away from the side you are working on once you get the tire off.
    I tugged back and forth on the Vise-Grips more times, and harder, than I thought I should have to, and then, when I was just about to say, "Crap, it didn't work," I felt the sensor give a tiny "TICK". After that, it moved a bit more and a bit more, and I was able to lever it out easily with a screwdriver.

    I tried for longer than I should have to get the new sensor into the hole, without success, before I got out the Dremel with the tiny sanding drum on it. The tiny sanding drum fits into the hole like it was made for it, and there is plenty of clearance for the tool with the wheels turned away, and I gave the inside a good long scuff, till it stopped throwing red dust, lubed up the sensor with grease, and it popped right in.

    Buttoned everything up, drove around the block, lights still on, turned off the engine (had it on the whole time - 18°, you know), restarted, went around the block again, lights went off, anti-skid working, all is well.

    Thanks again,

    - Eric

  4. #4
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    Using anti seize on the new sensor helps future replacements

  5. #5
    Join Date
    Aug 2009
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    Maine, USA
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    1998 318ti 2001 330ci
    Yes, and I had done that the last time I replaced this sensor, so I tried a very thick grease that I like this time.

    215,000 miles, and one sensor has gone bad twice.
    The replacement was a genuine ATe unit from Pelican both times.

    - Eric

  6. #6
    Join Date
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    UK
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    2007 BMW 118d
    My rear right ABS sensor looked really seized and feared the worst, however I got it out with relative ease. (Issue was upward spikes on the sensor @ 80000 miles which meant traction control kept cutting in on left steering input whilst above light throttle).

    1. Jet some rust penetrant at the back of the sensor. Jet some to the sensor head (very little access here and possibly does not penetrate from this end).
    2. Using pliers or adjustable spanner with a some sort of soft jaw, twist the back of the sensor as much as you can in both directions to loosen it. In the end, mine probably only managed to twist 1degree!
    3. Hammer a small flat blade screwdriver between the back of the sensor and mating face (central between the mounting screw hole and the sensor head). If you're lucky, this will be enough to pop the sensor out without damaging it.
    4. Clean up the bore with a round file and rust penetrant or brake cleaner, so that the new sensor goes in with relative ease (may require a little a bit of twisting to work it in and out).
    5. Worth checking if there are any high spots on the reluctor ring. Push the new sensor in and turn the wheel to see if at any point the sensor is pushed out a little bit. Mine did, so rather than clean up the corrosion under the reluctor ring by removing the driveshaft, I used a 0.5mm washer to pad out the sensor. Probably gave an airgap of 0.5 to 2.0mm which seemed to be ok.

    Hope this helps!

  7. #7
    Join Date
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    I use fire also.. Set it on fire is my motto.

  8. #8
    Join Date
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    Quote Originally Posted by eroticelmo View Post
    My rear right ABS sensor looked really seized and feared the worst, however I got it out with relative ease. (Issue was upward spikes on the sensor @ 80000 miles which meant traction control kept cutting in on left steering input whilst above light throttle).

    1. Jet some rust penetrant at the back of the sensor. Jet some to the sensor head (very little access here and possibly does not penetrate from this end).
    2. Using pliers or adjustable spanner with a some sort of soft jaw, twist the back of the sensor as much as you can in both directions to loosen it. In the end, mine probably only managed to twist 1degree!
    3. Hammer a small flat blade screwdriver between the back of the sensor and mating face (central between the mounting screw hole and the sensor head). If you're lucky, this will be enough to pop the sensor out without damaging it.
    4. Clean up the bore with a round file and rust penetrant or brake cleaner, so that the new sensor goes in with relative ease (may require a little a bit of twisting to work it in and out).
    5. Worth checking if there are any high spots on the reluctor ring. Push the new sensor in and turn the wheel to see if at any point the sensor is pushed out a little bit. Mine did, so rather than clean up the corrosion under the reluctor ring by removing the driveshaft, I used a 0.5mm washer to pad out the sensor. Probably gave an airgap of 0.5 to 2.0mm which seemed to be ok.

    Hope this helps!
    While this is a very good description, it does not have much impact without pictures and /or definitions.

    1. What is the "Back of the sensor"?
    gmak: The Good, the Bad, and the Ugly. A journey with my new-to-me 2000 540i

    "Working on a BMW E39 is the best way to run out of time."

  9. #9
    Join Date
    Aug 2009
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    Quote Originally Posted by gmak View Post
    1. What is the "Back of the sensor"?
    The back of the sensor is the inboard end, out of which the wire emerges, which you can see and access, as opposed to the front, which cannot be seen without a decent amount of disassembly.

    - Eric

  10. #10
    Join Date
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    F90 M5; E36 M3 Turbo
    I have had very mixed luck removing abs sensors that have frozen or corroded in place over ten or more years. Often they break. But give it a try and pound the guts through if you fail.

  11. #11
    Join Date
    Jan 2017
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    Antwerp,Ohio
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    1991 318 is, 1995 318 ti

    stuck abs sensor 95 318ti

    Quote Originally Posted by MDchanic View Post
    Thanks for this writeup.

    The first time I changed an ABS sensor, I used plenty of KROIL, clamped on the Vise-Grips, twisted and twisted, from the outside only, thought I was getting it loose, and ended up breaking off the outside portion of the sensor.
    After that I had a bright idea and used a hacksaw blade to cut off the inside of the sensor, but the part that goes through the steering knuckle was still stuck in there.
    I had to remove the wheel bearing / hub in order to get clear access to the sensor hole, then I tried to pound the piece out with a ⅜" extension, but all that did was to make a ½" hole in the middle of it, so I had to finally pound it out with a socket the exact size of the hole and a BFH.

    Not wanting to repeat that, especially on an 18° day, I was glad to have found your simple piece of advice.

    I removed the wheel, caliper (to get access to the caliper bracket bolt that is partially blocked by the brake hose), caliper bracket, rotor screw, rotor, and the three little screws that hold the sheet metal shield assembly to the steering knuckle, to mobilize it a bit for clearance.
    I sprayed both ends with KROIL like there was no tomorrow, snapped two pairs of Vise-Grips on the two ends of the sensor, and started tugging back and forth in unison.
    I will note here that it is MUCH easier to do ALL of this if the front wheels are turned away from the side you are working on once you get the tire off.
    I tugged back and forth on the Vise-Grips more times, and harder, than I thought I should have to, and then, when I was just about to say, "Crap, it didn't work," I felt the sensor give a tiny "TICK". After that, it moved a bit more and a bit more, and I was able to lever it out easily with a screwdriver.

    I tried for longer than I should have to get the new sensor into the hole, without success, before I got out the Dremel with the tiny sanding drum on it. The tiny sanding drum fits into the hole like it was made for it, and there is plenty of clearance for the tool with the wheels turned away, and I gave the inside a good long scuff, till it stopped throwing red dust, lubed up the sensor with grease, and it popped right in.

    Buttoned everything up, drove around the block, lights still on, turned off the engine (had it on the whole time - 18°, you know), restarted, went around the block again, lights went off, anti-skid working, all is well.

    Thanks again,

    - Eric
    Thanks for your answer. I have a 95 318ti (with the 1.8 liter engine). When i went to change the front left abs sensor, it did not look like the replacement part. It had a stainless metal sleeve around the plastic sensor. The vice grip trick did not work at first. The jaws just slipped on the metal sleeve. Heating the tube with a torch and crushing the sleeve with the twin vice grips finally did work. It was still better than taking the hub apart. I use this site a lot .
    I have 2 91 318is' , a 95 and a 97 318ti. I really appreciate the information. Often the You tube videos are not exactly on point. Bimmerforum posts are. Thanks. far6car

  12. #12
    Join Date
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    No warranty of any kind implied or given and no liability for any loss, damage or injury, no matter how incurred accepted.

  13. #13
    Join Date
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    Does it rain every day in the UK? That is some crazy crusty stuff! Any plans to undercoat or rust proof your next car if it's a good example?
    Attn. NEWBIES: Use the search feature, 98% has already been discussed.
    Click the search button, select "search single content type", select the "e36 sub forum" specifically, try the "search titles" then try the "search entire posts".

  14. #14
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    Quote Originally Posted by Eric93se View Post
    Does it rain every day in the UK? That is some crazy crusty stuff! Any plans to undercoat or rust proof your next car if it's a good example?
    This car's still solid. Struts are disposable items
    No warranty of any kind implied or given and no liability for any loss, damage or injury, no matter how incurred accepted.

  15. #15
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    What did you use to drill a hole in the sensor to get the screw in there? I tried drilling it and got nowhere.
    Lime Rock Park... the most fun you can have in a mile and a half.


  16. #16
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    I either used a normal HSS drill to drill a pilot hole or wound the screw in without, I forget
    No warranty of any kind implied or given and no liability for any loss, damage or injury, no matter how incurred accepted.

  17. #17
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    I tried drilling a pilot hole.. even tried using a cobalt drill bit and couldn't get it to bite. hmmmm
    Lime Rock Park... the most fun you can have in a mile and a half.


  18. #18
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    Use a center punch.
    Attn. NEWBIES: Use the search feature, 98% has already been discussed.
    Click the search button, select "search single content type", select the "e36 sub forum" specifically, try the "search titles" then try the "search entire posts".

  19. #19
    Join Date
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    Quote Originally Posted by Eric93se View Post
    Use a center punch.
    Just don't knock it through
    No warranty of any kind implied or given and no liability for any loss, damage or injury, no matter how incurred accepted.

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