Hi Kevin

The idea of the concentric cross-shaft tubes is that braking effort is transferred from the offside pedal down the inner tube to the mid-point of the car (where it is pinned/welded), and thence back out to each side to the rear brakes. The inner and outer tubes may indeed have become rusted together. But even if they are free, they are both very stiff and the amount of differential twist between one and the other is tiny. This makes it quite hard to see even when an assistant is "standing" on the brakes and applying a lot of torque to the tube, let alone just levering it with hand tools when testing it off the car. Nevertheless, with mechanical brakes it is force which matters, not movement.

The main effect of seized tubes is that the now "solidly" connected rear offside brake tends to work harder than the "springily" connected rear nearside one when you are braking hard, and may even lock up in an emergency stop. To some extent you can allow for this by slackening its cable a tiny bit, but the rear brakes will never be balanced at all degrees of braking. What tends to happen is that as you increase pedal pressure, the nearside rear brake begins to work first, then the offside brake "catches up" and eventually exceeds it in effort. I have seen this during the MOT roller test.

The front brakes are reasonably balanced side-to-side by the half-moon compensator, and since they contribute more than 50% of the total braking effort a bit of imbalance at the rear doesn't seem to be a serious problem in practice.

Location: New Forest