brakes push back at me

[2.8broncoII]

98 ranger 4x4. it slows down fine. when it gets to around 3-5 mph the brake pedal pushes out all the way back and i cant push it down. 2 seconds pass then i can push it down again and come to a stop. i dont have any abs lights or dummy lights at all so im not sure where to start looking. the brakes are spongy and i need to bleed the system but that would not cause the problem would it?
any ideas guys?
dan

 

[Sasquatch_Ryda]

Sounds like false ABS activation to me. Usually caused by a bad wheel speed sensor/or tone ring.

You can replace the wheel speed sensors, but if it is a tone ring you need to replace the complete hub assembly on the fronts as they are inside them.

If you can, have someone monitor the speed sensors with a scan tool while driving/stopping to see which sensor is dropping off. That one is the problem.

 

[2.8broncoII]

is there a way to unplug the speed sensor to see if it is that first? they are located on the front brakes?

 

[martin]

sounds like a bad vacuum booster to me.

 

[2.8broncoII]

would a bad vacuum booster lead to any other problems?

 

[Sasquatch_Ryda]

Yes, you would need exert much more effort on the pedal to get it to stop.

The booster is what give you 'power brakes'.

 

[2.8broncoII]

i dont have to push hard all the time just when the pedal pushes back at me, otherwise the brakes seem fine. im going to check for vacuum leaks tommarow and replace any dry rotted pieces, ill get back to you guys.

 

[Yellowsplash]

Sounds like false ABS activation to me. Usually caused by a bad wheel speed sensor/or tone ring.

Pull the rotors and clean off the speed sensors. Inspect the tone ring on the back of the rotor for damage and replace if necessary.

 

[2.8broncoII]

the rotors come right off when the caliper is removed right? you dont have to take the wheel bearing assembly apart.

 

[Sasquatch_Ryda]

Pull the rotors and clean off the speed sensors. Inspect the tone ring on the back of the rotor for damage and replace if necessary.

His abs sensors go into the hub/bearing assemblies. And the tone ring is part of the bearing assembly as well. You can pull the sensor out of the hub to clean it, but chances are if there is a lot of metal stuck to it the bearing is hooped.

 

[Yellowsplash]

His abs sensors go into the hub/bearing assemblies. And the tone ring is part of the bearing assembly as well. You can pull the sensor out of the hub to clean it, but chances are if there is a lot of metal stuck to it the bearing is hooped.

Whoops....looked at the picture and over-looked the "98 ranger". Anyways, yes, the abs acting up is a good indication that the wheel bearing/hub assembly is going bad.

 

[2.8broncoII]

hope its not too expensive considering the truck only cost 200 bucks

 

[2.8broncoII]

can regular non abs 4x4 hubs be put on and just get rid of the abs stuff?