Haven't driven the car in a while. Store it with the emergency brake on. Took it for a spin recently and the brakes were grabbing. I tried to cycle the brakes and the emergency brakes. Brakes still grabbed.
May be some rust build up in the drums, it will wear off, but if the emergency break cable is frozen up a bit, could cause this also. You could see by lifting the rear end up and spinning the rear wheels, they should rotate with a slight drag.
Your car, and all Spiders, have disc brakes on each wheel. Does the brake fluid level on your car remain relatively constant or do you need to add fluid frequently? I had a Datsun with one rear wheel that locked-up when I used anything more than moderate pressure on the brake pedal. Turns out that I had a bad seal on the rear drum brake and the leaking fluid had softened the brake lining. My Spider had water in the brake fluid when I bought the car. As a result two caliper pistons were extremely rusty. A rusty piston could be hanging up in the bore causing the brake to drag. Also, water in the fluid could cause the valve in the rear brake compensator to hang-up. My Spider had no pressure to the rear brakes until I replaced this valve. Raising the car and checking for free rotation of the wheels, as previously suggested, is easy to do and a good first step to troubleshoot the problem..
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