I have replaced rear caliper, rotor etc. Bleed brakes, one side locks for me the other side will not engage, can still turn wheel with brakes applied. There was some fluid coming from line when bleeding, also when bleeding pedal would go right to floor, then come up but then right to floor again. I did replace a brake line that i saw leaking. Extra info, this car needs brakes done about every 4-6 mths. only one side gets hot and wears down, we usually take it in to garage to have done but with the problem occuring so many times thought we would do ourselves this time around

 

Did you replace the rubber line to both rear brakes. Also replace the caliper brackets and pins with new. This make sure they will work freely. The slide pins usually freeze up so they wont slip or stick so one side works harder than the other. Ive done this on all the SHO's Ive owned.