Jack coments,
Have you tried removing and cleaning the adjusters? They sometimes get sticky. The threads can be cleaned extremely well by gently holding them up to a wire-brush in a drill. I clamp my drill in a work-bench, or just step on it. You might want to use vice-grips to hold the adjuster (don't clamp the threads), safety glasses and perhaps leather gloves. This saves wear and tear on you.
There is a special grease that can be applied to the threads for re-installation. If you use regular grease, it may become too stiff in the winter, or contaminate the brake shoes, lubricating them and making them useless. If you don't have brake-safe grease, you could consider lightly oiling the threads with a motor oil, then wiping them off carefully, so no oil can get on anything else.
An old paint brush and a bucket of water can be used to rinse & brush away the dirt, dust and asbestos from the brake assembly. Dump lots of water over the area before whisking. Avoid inhaling!
I set my shoes initially (with the parking brake 'off') to a light drag. In theory, they are automatically adjusted by braking and by parking brake application. This does not always work.
If you don't use the parking brake, cables can rust and seize. There is an adjustment for the parking brake lever travel. I believe the specifications call for it to lock the back wheels in about 6 notches' travel. You can tell how the rear brakes are working by driving at low speed, on some loose sand, when no other people/cars are around, and pulling up on the parking brake lever. Keep the thumb-release depressed, because you'll want to let the brakes off at once to stop the skid.
Good luck with this veteran Tercel, a fine car.
- Jack