abs thump at slow stop.

[Paul hobbs]

I replaced the front wheel bearings and master cylinder. Master cylinder was fading at full stop. Pressure bled brakes. Now I have a bump and slight buzz in the abs system during a slow stop, around 3 to 5 mph. The brake pedal bumps slightly and the wheel will turn left slightly. I don't have any warning lights Brakes are firm and no fade. Brakes work perfect until I get almost to a stop. If I creep up on a stop, that is when it bumps and buzzes. and the brake pedal sinks slightly. Any Ideas why? 2WD XLT Explorer

 

[Turdle]

I would suspect something in the ABS sensor or wiring is not quite right. Is it possible you damaged a sensor? Grease or dirt contaminating it?


You might try disconnecting the battery for a few minutes to see if it will reset.

What were the issues you had before replacing the bearings? Did you have an ABS warning light displayed with old bearings ?

Which brings up another question, does the abs light illuminate when you first turn the key on?

 

[Kidd7]

I 2nd the ABS. My father had a 2000 Mountaineer in which the pedal would sink to the floor once the truck was at about 3 to 5 mph. The shop replaced the master cylinder, still the same problem. The shop test drove it with their ABS computer connected and could see when 1 sensor stopped sending a signal. Replaced that sensor and no more problems.

 

[RandomNerd2000]

3rd the ABS, my 01 was doing this exact thing occasionally, was a bad ABS sensor in the rear axle, changed it, problem solved

 

[239]

I replaced the front wheel bearings and master cylinder. Master cylinder was fading at full stop. Pressure bled brakes. Now I have a bump and slight buzz in the abs system during a slow stop, around 3 to 5 mph. The brake pedal bumps slightly and the wheel will turn left slightly. I don't have any warning lights Brakes are firm and no fade. Brakes work perfect until I get almost to a stop. If I creep up on a stop, that is when it bumps and buzzes. and the brake pedal sinks slightly. Any Ideas why? 2WD XLT Explorer

Mine did the same thing. I replaced the sensors but it ended up being the actual rotors themselves. The abs tone rings inside of the rotors weren't working anymore. Hopefully it's only the sensors on yours.

 

[Paul hobbs]

I replaced the front wheel bearings and master cylinder. Master cylinder was fading at full stop. Pressure bled brakes. Now I have a bump and slight buzz in the abs system during a slow stop, around 3 to 5 mph. The brake pedal bumps slightly and the wheel will turn left slightly. I don't have any warning lights Brakes are firm and no fade. Brakes work perfect until I get almost to a stop. If I creep up on a stop, that is when it bumps and buzzes. and the brake pedal sinks slightly. Any Ideas why? 2WD XLT Explorer

Sorry for the delay....I found the problem. When I seated the grease seal after replacing the wheel bearing, the tone ring popped up about .050. It was rubbing on the sensor in about a 2 inch sector. Took a brass drift punch to the seating collar of the ring, checked it with a straight edge, and put it back together. Works fine now.
Thanks for the input, guys!