[Ascaris]

Let me get this straight. Your regular brakes work and the Emergency brake doesn't?

If you regular ones work fine, then it isn't your calipers or the brake mechanism itself. Most likely suspect is cable stretch.

Try adjusting your emergency brake cables. Put the car up on a hoist or stand so the rear wheels are free and put it in neutral. The adjustment nuts are at the end of the metal tubes where the cable passes through the firewall. Start with the Ebrake off and spin the tire by hand and adjust the nuts till the brakes engage then back off till it spins freely. Do the same for the other side then engage the ebrake and see how well it holds. You don't want it dragging, but want plenty of grip when engaged.

Good luck.

Ascaris