Help with ABS system

[valleyboy]

Can anyone tell me why my anti lock brakes pulsate when coming to a stop on dry roads.

Thanks in advance
Valleyboy

 

[jp450]

If you are sure that it is the ABS that is activating rather than a warped or glazed disk that is causing the pedal to pulsate, I would first check to ensure that all tires are inflated the proper pressure. A tire that is low will turn at a diffrent speed and the computer may see that as a condition to activate the ABS. Is the tread on all the tires good? If the ABS light is on have the code checked. If you can get to them, make sure that there is not some debris hampering the front sensors. Also is your speedo working properly? These are a few things that I can think of off the top of my head.

 

[BrooklynBay]

You could determine if it's because of a warped rotor or the ABS if you pull out the ABS fuse, and see if this still happens.

 

[valleyboy]

ABS Pulsating

If you are sure that it is the ABS that is activating rather than a warped or glazed disk that is causing the pedal to pulsate, I would first check to ensure that all tires are inflated the proper pressure. A tire that is low will turn at a diffrent speed and the computer may see that as a condition to activate the ABS. Is the tread on all the tires good? If the ABS light is on have the code checked. If you can get to them, make sure that there is not some debris hampering the front sensors. Also is your speedo working properly? These are a few things that I can think of off the top of my head.

 

[valleyboy]

Hi jp540
Thank you for the suggestions. Actually I replace the pads and rotors last spring but the truck has been siting and the mechanic said I need to clean (turn) the rotors due to the truck not being driven enough. I also noted last night that when I apply the brakes hard that I can feel the brake rotors thumping so I will get them turned and have the abs sensor cleaned. Maybe that's all I need. The light for the ABS has never come on. One last thing my mechanic told me I need to change the wheel bearing assembly to fix my pulsating brakes, do you think he is just after my hard earned money?
Thanks Valleyboy

 

[valleyboy]

You could determine if it's because of a warped rotor or the ABS if you pull out the ABS fuse, and see if this still happens.

 

[valleyboy]

Thanks BrooklynBay for your suggestion.
Valleyboy

 

[jp450]

Hi jp540
One last thing my mechanic told me I need to change the wheel bearing assembly to fix my pulsating brakes, do you think he is just after my hard earned money?
Thanks Valleyboy

I would get another opinion on that one...... I have never heard a wheel bearing causing the breaks to pulsate....

When a vehicle sits unused the disks will rust but the part of the disk under the pad will tend not to rust causing the pedal to pulsate...

 

[valleyboy]

Thank you kindly I'm in the process of having another mechanic check it out

 

[BrooklynBay]

Did you pull out the fuse to see if it's related to the ABS system prior to giving it to a mechanic?