Help. Cannot remove dead front ABS sensor.

[jpliddy]

my multimeter is LAP brand from screwfix it works as i set it to DC @ 20 volts and it gave a reading of 12.86 volts on battery terminals with engine switched off
is that ok too

[Laird Scooby]

Originally Posted by 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

That's the Continuity/Diode Test function you used Jim, really for a correct reading you need to look a little further round the dial to about the 11 o'clock position where it says 2k. Try that just to get the figures right but from what you've described, it's backing up the cars diagnostics - always good practice to double check the cars diaagnostics as sometimes a fault code can have more than one cause!

[jpliddy]

HI dave
ive done the test as you explained the good sensor gives a reading of 1.122
hopefully faulty sensor gives a reading of 1 which is there when i turn multimeter on before i touch probes to sensor so that hope means proceed to replace sensor
regards jim

[Laird Scooby]

Originally Posted by jpliddy

my multimeter is LAP brand from screwfix it works as i set it to DC @ 20 volts and it gave a reading of 12.86 volts on battery terminals with engine switched off
is that ok too

You hadn't long switched the car off there Jim! That sounds about right but a better test is 30-60 minutes after switching off, should be 12.6-12.7V but that will drop off over time due to things like the clock, any doors etc being opened (courtesy lights etc) and self-discharge.

Originally Posted by jpliddy

HI dave
ive done the test as you explained the good sensor gives a reading of 1.122
hopefully faulty sensor gives a reading of 1 which is there when i turn multimeter on before i touch probes to sensor so that hope means proceed to replace sensor
regards jim

What you've read there Jim is 1.122k Ohms or 1122 Ohms which is about right for a good sensor. If the other is open circuit indicated by a 1___ with three empty spaces after (shown by the underscore "_") on the display then the other has a break somewhere in the cable or the sensor.

Swap them over, pull fuse #1 (think it's #1 on the D24) for 30+ seconds and refit and that should reset the fault codes in the ABS ECU. There is another method of switching the ignition on and off quickly 20+ times but that can lead to blwon fuses in unrelated items so isn't recommended!

[jpliddy]

well folks
i thought i was making progress with removal of the faulty sensor . i got some movement with mole grips and easing oil on the inside of sensensor only to find it came away leaving all the gubbins in the bore hole which is rock solid .so its a wheel of calliper off and disc off when i get chance and hammer and punch and drills to get the sensor out of the bore hole plus maybe reamer bits too and cutting abrasive paper !!
on the plus side i tried the new sensor on car and the ABS light went OFF so its looking like its the sensor fault .

[Ian21401]

Originally Posted by jpliddy

well folks
i thought i was making progress with removal of the faulty sensor . i got some movement with mole grips and easing oil on the inside of sensensor only to find it came away leaving all the gubbins in the bore hole which is rock solid .so its a wheel of calliper off and disc off when i get chance and hammer and punch and drills to get the sensor out of the bore hole plus maybe reamer bits too and cutting abrasive paper !!
on the plus side i tried the new sensor on car and the ABS light went OFF so its looking like its the sensor fault .

Don’t dismay Jim. I removed the wheel, caliper and disc before even starting to try to remove the sensor. The sensor eventually came out in pieces as you will see from the write up did. See post #6.

[Laird Scooby]

I used (among other things) a sanding drum on an air die-grinder (Dremel with attitude on steroids) to clean mine out on my last 740 then polished the bores to a mirror shine after slightly enlarging them then fitted the new sensor with plenty of silicone grease round the body of the sensor (but NONE on the tip ) to help prevent further corrosion.

Oddly when i had to do the right hand one on my 760 recently, one tap from a parallel punch with the lump hammer (gentle tp as well!) sent both halves of the broken sensor flying out.
Gave it a quick clean up, silicone grese on the body of the new one, fitted, tested, back to what it was doing before the sensor broke.
Still had a problem but that's a totlly different story!

[jpliddy]

just like to say thanks for all the input on ABS light on subject
i have now fitted a new ABS sensor and the ABS light goes off
i had to take every thing off including wheel bearing and brake dust sheild
to get full accesss to the old sensor so drilled it out and cleaned the bore hole so all went really well no rushing and plenty of Tea ! no ABS light on now!
another job of the list
ive been told i should have inspected wheel bearing and regressed it so i missed that sorry what spec grease is it any body know?
thanks again
regards jim

[Laird Scooby]

Originally Posted by jpliddy

just like to say thanks for all the input on ABS light on subject
i have now fitted a new ABS sensor and the ABS light goes off
i had to take every thing off including wheel bearing and brake dust sheild
to get full accesss to the old sensor so drilled it out and cleaned the bore hole so all went really well no rushing and plenty of Tea ! no ABS light on now!
another job of the list
ive been told i should have inspected wheel bearing and regressed it so i missed that sorry what spec grease is it any body know?
thanks again
regards jim

The wheel bearing is fitted permanently in the hub Jim, is that correct? As you pull the hub off, the entire bearing comes with it?

If so, you can't regrease them, if it's the older type (but fairly sure yours is new enough to have the all-in-one jobbies) that has the conical bearings, a molybdenum sulphide based grease is good. It's waterproof and thick enough for wheel bearings and has good load capabilities too.

[jpliddy]

hi dave
yes the whole wheel bearing come out together . but the centre bearing part is in 2 half i did not realise this years ago when i replaced the front dust guards i pulled the wheel bearing off and not realising the centre bearing just came apart and ball bearing fell on the floor i panicked and got the unit all back together and put it back on the HUB it was a good few years ago now i suppose thats another job on the big list replace complete wheel bearing unit . but i think they are very expensive . the good quality ones anyway.