[rbohm]

Not sure what the spec is, offhand, but it looks to be like maybe 80% of the lining still remains.

The shusshing sound you describe is an out-of-round condition, but unless it is causing shaking when you brake, it may well be too minor to warrant correction.

If the rear brakes are giving very little power, you may need to rebuild or replace the wheel cylinders. A stuck piston will reduce effectiveness of the brakes that much quite easily.

i agree with this assessment. if you do anything with the wheel cylinders, order up new ones, but get the V8 wheels cylinders, especially for the rear, as they have larger pistons and put more pressure on the shoes for better stopping power. a small increase to be sure, but one that can be felt, i did this with my 64 falcon and it did make a difference.

as to the shusssing sound, again i agree that ir may be out of round drums. my suggesting would be to pull the drums and check them, or have them checked, for roundness on the braking surface and find out if they are out of round, and by how much and go from there. that said, if the brake pedal is not pulsing when you are braking, then leave them along.