1998 cavilier abs problem

[motorcitymik]

When in abs braking mode the unit feels and sounds like its about to rip off the brake booster. Additionally it locks up a different wheel randomly,(abs not working at all)No light no codes.

[Meccboy]

Possible a problem in the motor pack. The black housing on the unit.
Have had a few of the gears on the bottom side of the motor pack come loose and cause weird operation and sounds.
You would either need to remove the master cylinder and assmbly all at once, then remove the cover on the bottom of motor pack, or try to do it dtill on the car to inspect the 3 gears. Either way, try to do it without removing the brake line, as this will casue air in the system and it is a pain to get out.
If a nut on a gear is loose, MUST hold the gear when tighteneing the nut.

[Ronny334]

It does sound like one of the gears on that ABS motor pack are loose. This would cause the whole thing to be unbalanced and vibrate violently. Have a mechanic check those gears first. If you're going to do it yourself the post above by Meccboy is right on the money. That is a good description on how to remove the ABS unit and check and/or tighten those gears.

[JaneMoore]

I had a similar problem on my Chevy Cavalier. The ABS light came on every time I hit the brake pedal and just before the car came to a complete stop, the front it would shake really bad. I took my car to the mechanic and he scanned the computer and said the left front speed sensor had a problem. After looking into it further he found out it was not sensor at all. It was something about a large ring on the axle that the sensor reads. That thing was cracked and he said every time the speed sensor saw that crack it would mess up the ABS computer reading. So he replaced the axle and the problem is fixed. Hope this was helpful to anyone else with a Chevy Cavalier.