Hi George,

I know, that there are two brake regulators at the rear axle:
1st the braking force regulator (engaged by a lever and a spring in dependency on the load of the car)
2nd the braking force limiter (engaged by centrifugal force during faster cornering, to prevent locking of the inner curve wheel)

But I´m sorry, cause I can´t see the coherence of your front brake overheating and the braking force regulator. Rusty brake disks on the rear axle might seriously be caused by a braking force regulator malfunction. If the brake pressure is too low, the braking action is even too low. In extreme, the braking action is near zero.

But I see no coherence between the front and the rear brake, when the braking force regulator is defective, because the regulator controls only the pressure at the rear brakes.
Front break overheating is very often the result of tilted caliper pistons or damaged, respectively dirty / clogged master cylinder. In the last case, is it possible, that you have rinsed the dirt while bleeding the system after renewing the regulator?

Beste Grüße
Tim