And I'm pretty sure the cause is the e-brake caliper itself in that the pads are to far from the rotor and the hand brake linkage only moves the pads so far and no farther. I THINK the e-brake calipers are supposed to be "auto adjusting" in that they keep the pads a set distance from the rotor. It's obvious that for the most part the "auto adjust" feature does not work after a very short time. Requiring you to make a manual adjustment of the clearance and cleaning/lubing the auto adjust mechanism ON the caliper itself. When all works as it should the e-brake is actually quite strong and will hold the car very well, but it's maintenance intensive and extremely difficult to access.
Here's a link on how to access adjust the e-brake caliper. Something about it being an 8 hour project....
http://www.jag-lovers.org/xjlovers/x...earcaliper.htm