Help. Cannot remove dead front ABS sensor.

[Laird Scooby]

Originally Posted by jpliddy

hi all
i will hopefully soon be doing this job to fix my ABS problem .
ive done the fault find with the on board fault finder it flashes
1-5-2 which indicates front right abs sensor fault .
i have ordered 1 of ebay less than £20 BRAND lexmark
so just hope i can perform the job ok
i will remove calliper and brake disc . i have various drills but no dremel
wish me luck !

If you can remove the disc and caliper Jim, undo the cap screw (Allen key) securing the sensor to the control arm and then from the outside, use a parallel punch and a hefty hammer to drift the sensor out - you may be lucky that way and it pops out with just one or two taps from the hammer via the parralel punch.

[TonyS9]

Once you get it all out, give the hole a good clean, sand if necessary, grease and when putting in the sensor do not twist it after putting it in. You need to line it up before tapping it home.

I broke my replacement by twisting it, seems to break the coil when the shell twists against the base. Maybe it was the cheap replacement, but pretty hard to justify £150 against £25.

[griston64]

Originally Posted by jpliddy

hi all
i will hopefully soon be doing this job to fix my ABS problem .
ive done the fault find with the on board fault finder it flashes
1-5-2 which indicates front right abs sensor fault .
i have ordered 1 of ebay less than £20 BRAND lexmark
so just hope i can perform the job ok
i will remove calliper and brake disc . i have various drills but no dremel
wish me luck !

I got mine out with a big hammer and an old screwdriver

[Ian21401]

Good luck Jim.
I accept that the fault finder indicates front right ABS sensor fault but suggest that before you start fighting to remove the sensor check it’s resistance if you can. I believe that it should be about 900+ ohms. When I did mine I found that the good sensor on the front left was 1080 ohms but the dead one on the front right was infinity. It could save you a lot of work as you may just have a wiring fault which is triggering the warning.
My replacement sensor was a Bosch, 0265001231, £55.00 from my local Bosch agent. I checked it’s resistance prior to fitting. It was 1093 ohms.
If you are thinking of acquiring a “Dremel” type tool then Machine Mart sell a cordless kit at a reasonable price. Mine has proved very useful for a multitude of tasks and the genuine “Dremel” accessories like mini cutting or grinding discs fit mine and are available to be bought separately at the likes of B&Q.
The Machine Mart kit is the Clarke CRT40, £36.00. The flexible drive wasn’t included when I bought mine.

[Laird Scooby]

Originally Posted by Ian21401

Good luck Jim.
I accept that the fault finder indicates front right ABS sensor fault but suggest that before you start fighting to remove the sensor check it’s resistance if you can. I believe that it should be about 900+ ohms. When I did mine I found that the good sensor on the front left was 1080 ohms but the dead one on the front right was infinity. It could save you a lot of work as you may just have a wiring fault which is triggering the warning.
My replacement sensor was a Bosch, 0265001231, £55.00 from my local Bosch agent. I checked it’s resistance prior to fitting. It was 1093 ohms.
If you are thinking of acquiring a “Dremel” type tool then Machine Mart sell a cordless kit at a reasonable price. Mine has proved very useful for a multitude of tasks and the genuine “Dremel” accessories like mini cutting or grinding discs fit mine and are available to be bought separately at the likes of B&Q.

Good points there Ian, the sensors should be somewhere in the region of 800-1200 Ohms but even a faulty one can present as ok on the resistance test. A dead short or open circuit (infinity) resistance is a sure sign though. The connectors for the front ABS sensors are mounted on the suspension turrets so it's easy enough to test them with a multimeter, if you have an assistant one can operate the meter ensuring good contact in the plug while the other wiggles the cable down to the sensor. This can reveal an intermittent break in the cable to the sensor, far more common than many realise!

It might also pay to reset the ABS fault code memory and see if the fault recurs. Also if it does, try cleaning the tip of the sensor and resetting the codes then test drive it. It may be something as simple as a build up of brake dust on the sensor tip (brake dust is a mix of various things including steel) causing a problem.

[jpliddy]

hi
thank you all for your input i have a cheap multi meter that works as i put a test on the battery and it read the correct voltage i have tried it on the terminals under the bonnet but could not get any readings im not very good with the electrical side of things . the new sensor has arrived . what multi meter settings do i use to test the new one then check the one on the car ?

[jpliddy]

hi all sorry about this i have just tested my new sensor i put the multi meter switch to the mark which looks like a concorde shape with a bar through it and it gave me a reading of 1100 flukuateing so i will test the ones in car tomorrow !

[TonyS9]

Originally Posted by jpliddy

hi all sorry about this i have just tested my new sensor i put the multi meter switch to the mark which looks like a concorde shape with a bar through it and it gave me a reading of 1100 flukuateing so i will test the ones in car tomorrow !

Diode test?

https://www.google.com/search?q=diod...qbecrektx38aSM

Should in the range 0 to 1. They normally display the voltage across a junction after applying a small current.

1 is open and bad, 0 is short circuit. You should get something in the middle or close to short (0) on a ABS sensor, which is just a very long wire for DC testing purposes

[Laird Scooby]

Originally Posted by TonyS9

Diode test?

https://www.google.com/search?q=diod...qbecrektx38aSM

Should in the range 0 to 1. They normally display the voltage across a junction after applying a small current.

1 is open and bad, 0 is short circuit. You should get something in the middle or close to short (0) on a ABS sensor, which is just a very long wire for DC testing purposes

Some multimeters will show 1100 on the diode test as the meter displays the voltage as if it had passed a constant current through an unknown resistor Tony. It's a good approximation but the resistance range really needs to be used.

Jim - use the range that has 0-2k and then an upside down horseshoe shape.



On that image, the resistance range is at the top of the dial and you can see the Omega symbol like an upside down horsehoe about the positions marked as 200 2k 20k 200k 2M 20M 200M. That's the range you need to use for checking resistance of the ABS sensors. I have no idea what multimeter you've got, they all vary to some degree but that said, if you know what to look for, they're all the same really.

[jpliddy]

hi dave thanks for your input and all of you too
i see the multimeter i used the continuity test position about 10 o clock on your dial on the said faulty side i got no reading on meter but on the good side i got a reading of about 1086 so the fault is matching the car fault finder is that ok do you think
regards jim