What would cause a rear wheel to lock up 1997 Ford Aspire?

Answer 1

Defective brakes, or wheel bearing.

Also some times the E-brake can stick on these cars, my rear wheels were locked up and i discovered this was the problem, i replaced the cable and i have not had any trouble since

A lot of times the rear wheel cylinder goes bad and either freezes up or starts to leak fluid onto the pads causing the brakes to lock up on that wheel.

if your vehicle is using drum brakes on the rear sometimes the friction material attached the the brake shoe can break off if they haven't been serviced in a long time and get wedged causing the wheel to lock up, rotating the wheel backwards may free the loose material but you will need to disassemble the rear drum and inspect and replace and defective parts

It would really help to know what vehicle is involved---and what action caused the wheel to lock up---on rear wheel drive vehicles with a differential the oil from the diff can leak out the end of the axel housing onto the brake shoes --then the brake dust and oil mix and turn into an extremelly tacky compound virtually eliminating the clearance between the linings and the drum so the slightest brake application causes the wheel to lock up. On all vehicles the emergency brake hanging up can cause the extra pressure of the service brake to cause premature lock up. Brake fluid leaks are not a common cause because fluid is very thin and water soluable so puddles wash it off easily. Neither is the pressure differantial valve likley. Seized wheel cylinders cause excessisve wear not a typical lock up problem.