1995 850...ABS/TRACS problems...still

chef · Post by **chef** » 24 Mar 2009, 21:02

Hi guys, Since i got my car this past summer, I am always hearing a "ticking" noise when applying brakes, at lower speeds. When applying the brakes, i get the ticking, then the pedal vibrates/grinds(ABS), and comes to a stop. Lately it seems that the TRACS wanted to join the fun...and at times when taking off from a stop the TRACS grinding kicks in and i have to lightly apply brakes for it to stop working and the car works okay.
The thing is that i know that the pre-96 850's had a more robust ABS module and i'm wondering why this is happening? I was thinking maybe dirty sensors and/or speed sensor rings? I also did a full brake bleed on the car. I tried to take off the screw holding in the right left ABS sensor on the caliper but snapped it. I don't to have all broken screws on my case. Is there another way to clean out the ABS sensors? can the problem be something else? also, where is the ABS module located on a 95 850? thanks
fabs

Post by **Ozark Lee** » 24 Mar 2009, 21:59

The places to clean the sensors on the early ABS systems is the reluctance rings on the axles (front) or the hubs (on the rear) They are magnets that tend to collect the metal that has worn off of the brake calipers. The sensors are just above the rings and they will get cleaned in the process.

The front rings are directly behind the hubs but you can get to them without really removing anything. The rears are located inside of the drums for the parking brake and you need to remove the calipers and the rotors to get to them. Here is a picture of the rears. This is before cleaning it up:

: DSC01920.JPG (218.55 KiB) Viewed 6306 times

This is after I cleaned it up:

: DSC01924.JPG (215.33 KiB) Viewed 6330 times

I used brake cleaner on mine, others will argue about that but I have had no ill effects since I did this in 2006.

...Lee

chef · Post by **chef** » 24 Mar 2009, 22:38

Hey LEE thanks for the reply and pics...good stuff! TBH i've never worked or removed any of the brake components (roters, calipers..ect) is it really difficult? i have air tools in the garage...
for the fronts though..are they this simple? any info would be great..thanks
fabs

Post by **Ozark Lee** » 25 Mar 2009, 07:38

The reluctance rings are behind the hubs on the front wheels, they are set in kinda deep but you should be able to get to them.

...Lee

chef · Post by **chef** » 27 Mar 2009, 20:12

Hey Lee... so what are some of the symptoms if the rings are dirty with particles? have you ever had this problem of dirty rings? thanks
fabs

Post by **Ozark Lee** » 28 Mar 2009, 06:12

The rings have magnets in them and the sensors for the ABS/Tracs read pulses from the rings with a "hall effect" sensor. As the rings fill up with metal from the brake rotors as they wear down the pulse from the magnets is weakened.

I never did have a problem with the ABS or the Tracs but since I was there fixing my parking brake on my '94 I cleaned them up as a preventative measure while the rotors were being turned.

On my '96s the ABS problems were with the modules on both of them so I just repaired the modules.

...Lee

Tapsa · Post by **Tapsa** » 30 Mar 2009, 00:21

Hi, if you suspect tracks, then check also wiring and signals from front sensors. Do you get any DTCs? Got once bad signal from right rear sensor and replaced it and ABS warning went away. 850-94.
Br Tapsa

arsenal6 · Post by **arsenal6** » 03 Jun 2009, 01:59

hey guys kind of off topic here...but my car whenever i turn it off lately it grumbles/vibrate the duration is becoming longer now...kinda worried I think it the ABS?

It feels like it coming from the front wheels as suppose to anywhere else. My ABS sensor light comes on often even during a normal drive with no slip or slide...also it does vibrate rarely when i brake...could that be a issue? Any ideas?

Thanks for your help

Post by **Ozark Lee** » 03 Jun 2009, 14:55

arsenal6 wrote:hey guys kind of off topic here...but my car whenever i turn it off lately it grumbles/vibrate the duration is becoming longer now...kinda worried I think it the ABS?

It feels like it coming from the front wheels as suppose to anywhere else. My ABS sensor light comes on often even during a normal drive with no slip or slide...also it does vibrate rarely when i brake...could that be a issue? Any ideas?

Thanks for your help

What year is your car?

...Lee

arsenal6 · Post by **arsenal6** » 03 Jun 2009, 16:53

O sorry my car is a 1996 850 GLE