tracnblack,
Yes the slippers are a pre-fabbed version of the older style liquid/paste style anti-squeak compounds. The ones on the Sport Trac's factory pads are claimed to be stainless steel, while I have seen some made of a fiberboard/plastic like material.
Slippers prevent the back of the pads from rubbing against the caliper pistons or caliper body and creating that metal to metal squeaking noise.
Ford calls them slippers, while I've also heard them referred to as Isolation pads and anti-squeak pads.
The tabs on the pads are the square or hook shapped protrusions on the leading and trailing edges of the pad backing plate and keep the pads from falling out of the caliper. The tabs fit in a notch or slide on a machined rail on the caliper's mounting frame. As the caliper slides on it's mounting pins, the pads slide in and out on the caliper frame. All this does is keeps the caliper and brake pads centered over the rotor.
The Ford caliper and mounting frame as a notch that the square tabs fit into, and the notches have a flat-spring liner to keep the pads from rattling, and perhaps to help reduce the squeaking, but neither the slippers nor the springs are working. Lubing the tabs is the only solution for the Ford pads.
If you get some better quality brake pads (I paid $70 for Raybestos Quiet Stop, Carbon/Ceramic pads) and they had stick-on slippers that had a bit of a cushion built in wich I'm sure helped deaded any vibrations. That coupled with a dab of brake grease on the tabs, and you won't have any brake squeak.
...Rich
