DEADLY ABS Be Warned

[Lee_Coupe]

right bit of a weird one this...........

driving along and ABS light comes on, not a problem and brakes work as normal, HOWEVER when the ABS light randomly goes out i lose all braking, pedal goes rock solid and honestly have to brakes at all, totally sh1t myself first time it happened and thank god i have a good handbrake!!


anyways i have now disconnected both front ABS sensors in the engine bay and brakes now work fine (although still have no ABS obviously)

is this weird (and dangerous) ABS fault due to a dodgy front sensor?

I would urge all E30 Zone members to investgate as soon as they get any ABS warning lights flashing on and off rendomly because as i said i was left with a rock solid pedal and no brakes at all!!

I will also add this is the second E30 (one F reg and one G reg) i have had the EXACT same problem on, on the last one i just left it disconnected for goosd as a sensor change didnt seem to fix it.

[Martinaston]

When was the last time you changed the brake fluid ?

[Lee_Coupe]

about 6 months ago

[Martinaston]

The only things i can think of that would make the pedal go solid is either a vacuum leak on or near the brake servo or a problem with the ABS pump.

When you changed the fluid how did you bleed the system ?

[Brianmoooore]

ABS system is designed to be failsafe. I've never heard or come across anything like this.

[Jon_Bmw]

Lee did you get a crunching noise or just a rock hard pedal?

Also was it at all speeds?

[Lee_Coupe]

i agree that the ABS when failed is supposed to be failsafe and mine is when the light is ON but at random intervals the light will go out indicating the system is working..........

its when the light is out that the troubles arise. no real noise or vibration its just a soldi pedal and no brakes at all.

my 1990 325i sport did the same thing years back but that was just as deadly in that it appeared to randomly just direct fluid to teh brakes on one side of the car when the ABS light came on. nearly ended up in the central reservation twice because of it.

i cant be the only person to of experienced this

[Jon_Bmw]

Certainly sounds strange Lee. That problem with your old sport sounds extremely lethal, bet you sold that quick

Things to start doing are to check the resistance on the abs sensors, see if they are all about the same, a basic voltmeter will do this.

It sounds a bit like a problem I once had. When the abs light wasn't lit and i pressed on the brake pedal, i got no braking force at all and a crunching noise. This sometimes brought the abs light on and then the brakes operated fine. As you know it turns off the abs and the brakes then work fine. My problem turned out to be a faulty front nearside sensor which once replaced made the abs work fine.

Just my 2 cents, but for 2 mins work, you'll be able to rule out the sensors.

[Simon13]

sounds very odd i have never suffered anything like this either!

[stuartgallafant]

sod that! sounds lethal!!!

[fuzzy]

occasionally my brake pedal would go rock hard as well,but no abs light, since i have removed my abs it has never happened again. wether its connected or coincidence though i have no idea

[Brianmoooore]

Check that there is a tiny bit of slack in the pull rod across the car. I don't think this is anything to do with ABS.
BMW use a Bosch system also used by other makes, and there have been no recalls, either by BMW or other manufacturers.
If there was a fault it would still be the subject of a recall, even now, 12 years after productio0n ended.

[lefty325i]

I have seen this before not on a bmw however and it was to do with the ABS pump.