Abs Warning Light Comes On

[1708]

Hi All,

I have a 1994 320i Auto Saloon (129000 mls) The ABS warning light keeps coming on and going off at different intervals (there is no pattern to the timing) I have tried to remove the rear sensors but after removing the retaining bolts I cant get them out. Any tips on removing them or should I be looking for something else. Can they be tested?

[Guest Mister Dabsy]

Because of the dificulty you're having trying to remove them, they must've been in for quite a long time if not originals...

Having said that, try cleaning them "in-situ" and also the "fins" on the inner side of the discs... Cheap fix if it works ;)

How old is the fluid?

[1708]

Because of the dificulty you're having trying to remove them, they must've been in for quite a long time if not originals...

Having said that, try cleaning them "in-situ" and also the "fins" on the inner side of the discs... Cheap fix if it works ;)

How old is the fluid?

Thanks. Ive had the car for 10 years and Ive never changed them. Could you be more specific by "in-situ" and what are the" fins" on the inner side of the disc? At the moment its on axle stands as Im renewing the the discs and all I can see is the sensor with no visible access, just the back plate. Does this have to come off? The fluid is about 5 years old, but why do you ask? Anyway thanks for answering my post. Cheers!

[Guest Mister Dabsy]

Right, I would flush the fluid with new stuff.

Remove the plate and clean what you can, thoroughly.

[IanIOM]

Agreed give everything a clean and your be fine

[1708]

Agreed give everything a clean and your be fine

Thanks Fellas,

Ill try that tomorrow and let you know how I get on. Ive been in the bmw lounge and seen the same problem so Ive got two lines of attack! Whats your view on buying a diagnostic tester to use with a laptop? Have you got/used one? If so what one have you got/used?

Thanks for replying.

[karlos2010uk]

Hi Pal, i would hold off buying the diag software, i have the same issue as you and i have also got the 1994 320i, i bought the diag software from ebay.... see my other thread... http://www.bmwowners...stics-software/ i cant get it to work... so not sure it is compatible with my ecu.... waiting on confirmation from Ian and what software version he has... i bought the 1.3.6 software and scanner...

So far i have replaced both front sensors and still have the issue....... when Dabsy says clean the fins in inside of disc... there doesn't seem to be any... i have had the disc off completely and the ABS sensor actually goes into a totally enclosed housing and i can only guess that you have to take the hub and wheel bearing off to get at that...

[Guest Mister Dabsy]

CarSoft !!

[karlos2010uk]

CarSoft !!

Carsoft??? do you have any more details you can give ta....

[karlos2010uk]

No need for info on Carsoft.... just read a some details on what it is, sounds like a very good piece of software...

[1708]

Hi Pal, i would hold off buying the diag software, i have the same issue as you and i have also got the 1994 320i, i bought the diag software from ebay.... see my other thread... http://www.bmwowners...stics-software/ i cant get it to work... so not sure it is compatible with my ecu.... waiting on confirmation from Ian and what software version he has... i bought the 1.3.6 software and scanner...

So far i have replaced both front sensors and still have the issue....... when Dabsy says clean the fins in inside of disc... there doesn't seem to be any... i have had the disc off completely and the ABS sensor actually goes into a totally enclosed housing and i can only guess that you have to take the hub and wheel bearing off to get at that...

Thanks for the input. Yea I think I'll give the diagnostic whatsit a miss. Because I wanted to change the rear discs I have concentrated on the rear sensors. There is no access to them as they are behind the hub so I thought I would battle on and try to change them. WELL! if you have to go down this very rocky road then don't bother with a swear box, get a SWEAR BUCKET! They were an absolute pig to get out. The way I managed to do it was I removed the retaining bolt and forced an old screwdriver underneath and then broke the top off of the sensor. I then worked the same screwdriver down the side and prised it out bit by bit. I also slid a larger screwdriver between the top of the halfshaft and gently forced it up from underneath. It took me ages but I managed to replace both rears. I have also replaced the fluid. I bought the two sensors for £35.98 on ebay er' I can't find the address at moment. So far it seems to have cured the problem but I'ii give it a good run out on the weekend and let you know if it worked. Cheers

[Guest Mister Dabsy]

Well done mukka... We like the "Hands-On" approach :)

[karlos2010uk]

Smashing, just driving a few meters would light the ABS up again if there was still a problem so if you no lighty no faulty... i had the same issue removing the front drivers..... once there stuck there well and truly stuck no option but to smash them out.... maybe i should of started on the rears... thanks for the update though steve...

[kirby williams]

some abs systems have the other half of the sensor in the wheel bearing .... its a magnet of some kind i think so the fins dabs was on about might not b on yours or a ring round the driveshaft that looks like a cog the top of the teeth are what the sensor reads. if u have the time to leave it over night run wd40 all round the sensor and next day gently try to twist the sensor out ..... i usualy break them so have new ones ready or another way to get them from the shop

[kirby williams]

as for brake fluid i change mine every 2 years along with the gear box n back axle but im just anal lol

[Guest Mister Dabsy]

Deffo fluid change - And you're right Kirby, the rotor-fin system was unreliable in that they clogged up to often - magnet system was much cleaner way to send sig. !!

[1708]

some abs systems have the other half of the sensor in the wheel bearing .... its a magnet of some kind i think so the fins dabs was on about might not b on yours or a ring round the driveshaft that looks like a cog the top of the teeth are what the sensor reads. if u have the time to leave it over night run wd40 all round the sensor and next day gently try to twist the sensor out ..... i usualy break them so have new ones ready or another way to get them from the shop

I left them for 3 days with as much WD40 as I could get on. Also squirted some more every day, but the little darlings didn't want to come out! and also its got what looks like a cog underneath the sensor

[1708]

Well done mukka... We like the "Hands-On" approach :)

I wish they were someone elses hands!