Hi
Ive got a problem with my 2013 left hand drive Qashqai J10. It failed its MOT because of weak braking at the rear. It also felt like the car was pulling to the left at the rear when braking hard. Also the pedal was sinking when it was pressed.
So I replaced the callipers on the back and the master cylinder. I'd changed the front callipers a month or so before the MOT because they where sticking.
Bled the system up (sequence: Left rear, right rear, left-front, right front) and changed the brake fluid for new but the pedal was still sinking badly. The pedal would go all way to the floor and spongy. Tried and tried to bleed it with litres of fluid but nothing. Tried with a pressure bleeder, a vacuum bleeder and manual bleeder but no luck.
Changed the master cylinder again because thought I might of damaged it with the pressure bleeder but nothing. Spoke to a mechanic near by and he thought it could be the ABS pump so changed that. Still the same. So changed the Brake Servo. Still the same! Changed the front and rear flexi pipes. Still the same!
I've checked all the callipers individually to make sure they're all moving properly and they all are.
The only thing Ive noticed is that the fluid that the fluid pressure from outlet at the front of the master cylinder (furthest from the bulk head) is a lot less than the outlet at the back of the master cylinder (closest to the bulk head) but I don't know if its supposed to be like that. Also its the 3rd master cylinder that ive fitted to it (because I'm losing my mind!) highly doubt it an issue with the master cylinder.
Whatever I do the pedal is spongy and goes to the floor. Its like air is stuck in the system but Ive bled it and bled it but can't find anything. Ive also tried bleeding all the ports on the ABS pump individually by loosening each, one by one.
I've been trying to fix this for 6months and I'm out of ideas!! If anyone has had anything similar or knows a solution please let me know. I'd really appreciate it!
Thanks
Dave
