brake trouble

hello !! i'm new around here. this seems like a great place to get help with automotive trouble !

i own a 2001 ford explorer sport trac 4x4

i've been having a problem with my brakes. i've searched through about the last 10 pages of posts and havent seen too many similar posts so i thought i'd create a new thread.

the problem is a studder when i'm braking, not a pulsation from warped rotors, more like a slight skid and the pedal studders down about a quarter inch at a time, about 4 or 5 times. it does it about 70% of the time, and it feels to me like the anti-lock brakes are kicking in. this only happens when i'm coming to the completion of the stop. i just changed the front pads thinking that was the problem, but the problem persists.

so i guess i've narrowed it down to either the master cylinder or the antilocks. from what i've learned on here, maybe it's the anti-lock sensor ? how can i tell if it's the front sensor or the rear sensor, where are they located on the truck, where can i purchase one and what is the difficulty in replacing them ?

i hope that's not too many questions !! and i apreciate anyones help !!

thanks...... jay

Sounds to me like you have a wheel speed sensor that is not reading correctly. You might be able to clean them and cure the problem. They are bad about getting rust in the air bap portion and one wheel reads wrong. If you can find a scan tool rthat reaqds the ABS, you can isolate the one that is causing the problem.

thanks for the response ! where are those sensors located ?

I think you have 3. There will be one on each front wheel. Look inside the steering knuckle and you will see wires going to the sensor. These are the front sensor. The rear one will be on top of the rear end housing.

thanks way2old. as soon as i get a chance, i'll give that a try and post my results.

well, i went to a friend who has a scanner and it didnt find anything wrong. he said that the abs light has to be on to read an error. so, in the meantime of me getting to a garage with a better diognostics system, would it be possible to disconnect to abs system ? would it do any damage or make the brakes malfunction ? if i can, how would i disable the system ? which fuse would i pull ?

Look in the owners manual for the fuse. If you have no manual, go to www.fleet.ford.com and click on mainternance, then owners manual and enter the information. Go to roadside emergencies and you will find the fuse/relay layout. If your friends scanner can read the ABS data, have him hook up and drive the vehicle and watch the speed sensors. One of them will be off more than the other and will probably drop out at slow speed. That is your bad sensor.