I have a 2007 Prius gen II with 50,000 miles on it I took it for MOT ministry of transport annual test and it failed on rear brakes. The near side puled 82kg the off side puled 242kg I puled the pads and copper slipped the pads and sliders the piston pushed bake with ease reassembled them and re tested them witch increased the near side by 5kg. Has any one had this problem and how did you rectify it.
So problem is with normal brakes? And not with e-brake? E-brake is drum brake that is inside of a disc. If problem is with normal brakes and caliber sliders work: Try to bleed rear brakes with techstream. Rear bleeding can only be done with that and doesn’t require pedal pusher. If the amount/pressure of fluid getting out of both rear calibers is about the same and brakes still don’t work then you need to replace the caliber. If it really doesn’t bleed out from faulty brake there might be something blocked or more series brake problem.
It sounds like the caliper is binding up on the caliper pins instead of sliding freely so that the two pads get a similar amount of pressure. You might try replacing the pins first, if the problem continues maybe the caliper itself has to be replaced.