Nissan Repair: 1996 Nissan Pathfinder brake problems, nissan pathfinder, warped rotors

Question
Have a 1996 Nissan Pathfinder SE 4x4. New rotors, new brake pads. 3 mechanics have not idea why brake pedal jutters violently when getting ready to stop. Maybe it is ABS related? Where do I get a manual or diagram of ABS parts. Extensive search on google and could find very little about ABS sensors, expect from dealer and that was extremely expensive parts. Can you give us some direction as to where to proceed. Thanks  

Answer
Servi,

First, the new rotors are not warped.  Remember that Nissan rotors only torque lugnuts to 80 foot pounds and any more will warp them.  Baseline this by taking the rotors off and doing  radial runout test on them to see how far out of round they are.  Use only Nissan pads with true rotors and you should be fine.  Your ABS should not be coming into play at such a slow speed unless you are slamming on the brakes.  A rotor has to lock for the tone ring not to generate a signal.  If this happens then the ABS goes into action.  My money is on warped rotors and the wrong pads.  Now, there is one other thing that can cause this and that would be contaminated rotors where the mechanic got grease on the rotors or pads and that causes the pads to grab like you describe.  A good washdown with B-12 brake cleaner would solve this unless they really have a lot of grease on the pads.