My Citroen Saxo VTR recently failed an MOT due to the offside rear brake producing little or no effort. I had to replace the calliper, discs and pads on the rear of the car anyway, but this has not resolved the issue. The brake system has been bled a few times and this has had no effect on the brake. Also, when the offside rear is off the ground, the brake seems to catch. However, when on the roller tester it produces no effort. I bumped the car into the curb earlier in the year, due to the snow, and both the offside brakes are weaker than the nearside. Any ideas?