abs

[Jimbo92]

i just replaced both abs sensors on the front of my 97 mounty and the pedal still pulsates real bad right before i stop! it makes the truck keep rolling and i do not want the throw a wreck, is there another part that causes this? i just replaced the egr, egr pos. sensor, and two oxygen sensors and these front wheel sensors so i am extremely broke

 

[karl_burns]

Did you replace anything brake related recently?
When I changed my rotors, I got the same thing. Took them back to autozone, got a fresh pair, and it stopped. Weird, but it worked. I went to a lot of places to ask their opinion, and they all pointed to the rotors.
The only other thing is maybe there's some grease or something on the sensor that is blocking it from reading the magnetized ring in the rotor and activating your ABS correctly. Check those.
Karl

 

[cybercreeper]

i had a similar problem once. it ended up being the rotors. the place i took them to have them turned didn't do it right. it felt like they were wobbeling when i would press on the brakes. took the rotors back to have them returned. and whala. problem fixed.

The guy who did them the first time was new at it, so he didn't do it right.

 

[Jimbo92]

i put new brakes on the front including pads and rotors, shortly after i noticed the pulsating and saw the backs were toast, put on new pads and it continued. three months later the backs were toast again so i replaced the pads calipers and rotors. put abs fuse back in a still did it. i work at advance auto so i think ill swap my front rotors tommorow and see what happens

 

[philthejem]

abs sensors

there is another sensor in the rear diff
its in the top of the diff with 1 screw to hold it in
its the cheaper sensor!

i had the same problem with the abs kicking in just before i stoped
i replaced all 3 sensors and it cured it

you have to clean and scrape off any rust where the front sensors are seated
without geting anything in the hole!
if they arnt seated properly then they give a false reading like before
i stuffed a bit of cloth in mine when i cleaned them

hope this helps

phil

 

[Jimbo92]

i appreciate it guys i guess i need to change the back sensor

ford told me it was a part in the rear end and that it would be 900 dollars to fix it
i about told them where they could put that 900 dollars too

 

[Eneurb]

If it's a 4x4, there have been lots of problems with the air gap between the tone ring and the sensor. Pay attention to which way the steering wheel tries to pull as you are getting your false activation. If the steering wheel pulls right, you need a left hub, and vice versa. If the steering wheel does not pull at all, you proably have a problem with the rear sensor.

 

[Ranger Al]

Have you try bleeding your brake line? Lots of time when doing brake job, it is always good idea to bleed out the old contaminated fluid. If you air in the brake line would do such thing as well.

 

[pax]

Did you clean the ABS Sensor mounting surface before you put the new one in ?
False ABS activation at slow speed just before a complete stop on dry surface is usually caused by rust builded up underneath the front sensors.
Both of my trucks had the same problem. 95 Explorer and 97 Astro AWD van. After cleaning the mounting surface with a brass brush fitted on a drill fixed it. There was a GM bulletin regarding this problem. Cleaning the surface was the fix.