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View Full Version : Brake Failure only when pressing the pedal gently


paraklas
01-10-2021, 05:12 PM
Hi, quite recently, wife's 2002 (94000km) Yaris developed a braking issue, which i can easily replicate.

When I sharply (i.e. for immediate stop) press the brake pedal, it bites without any sponginess or other issues and car stops properly. Bite is at around 15-20% travel.

When I slowly press the brake pedal or modulate it just a bit, it will start to go down until it bottoms. There is minimal to no brake force and car continues to roll. I noticed that, while bottomed the minimal brake force is only applied at the front/right wheel (perhaps because it's the closest to the master cylinder?)

If I release and press back immediately, it will bite normally.

- Car was fitted new brake pads/disks last year, no issues till yesterday.
- New brake fluid yesterday but made absolutely no difference
- No leaks, brake fluid was always full
- ABS works fine

Took a video, sorry for my out-of-colour socks and speaking in Greek, narration is that I slowly press the brake or modulate it a bit till it hits the floor.

https://youtu.be/AL3zt1E2HiA

ghowey
01-17-2021, 12:26 PM
These are common symptoms of a failed master cylinder.