Brake pedal still sinks to the floor after master cylinder replacement
A sinking brake pedal usually indicates lingering air trapped inside the hydraulic lines or an internal leak within the anti-lock braking system (ABS) control module that standard bleeding cannot clear. When pressure bypasses the system valves, it forces you to pump the pedal multiple times to generate stopping power, preventing the vehicle from achieving immediate, firm braking.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1replacing the brake master cylinder
- 2bleeding the brakes
- 3pressing the brake pedal multiple times to build pressure
- 4Changing brake pads and shoes
- 5Checking calipers and wheel cylinders for leaks or failure
- 6Flushing brake fluid
- 7Checking or replacing the master cylinder
- 8Bleeding air out of the brake lines
- 9Disabling traction or stability control to test for changes
- 10Bleeding all four calipers starting from the one farthest from the reservoir
- 11Using a vacuum brake bleed kit
- 12Getting an ABS brake bleed service performed
- 13Using reverse bleeding or pressure bleeding methods
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“i replaced the caliper where the brake pad fell off, and both front rotors and brake pads. when i first tried bleeding the brakes, i left the spout open and just pumped the brakes but then learned that that doesn’t work because it fills the brakes back up with air.”source ↗
“does anyone know where i should go from here? i don’t have enough money for a mechanic and would like to do this myself if possible.”source ↗
“Hello, my brake pedal goes all the way to the floor when braking so I decided to switch out the brake master cylinder and bleed the brakes as well. I’m still having the same issue. Brakes go all the way to the floor.”source ↗
“Occasionally the brake pedal would work but I would need to press it 2-4 times to give it pressure and would work normally only for that moment.”source ↗
“When I am coming to a stop, the car before coming to a complete stop, it feels like the brake loses tension for half a second and the pedal goes down a bit & then it stops.”source ↗
Where this came up
People with this problem also raised
- 3Why is my brake pedal mushy after a service?
- 2Why do brakes still fail after replacing calipers and bleeding?
- 4Why is my brake caliper piston so hard to compress?
- 3Why does my steering feel loose and clunking?
- 4Why is my steering stiff after a CV axle replacement?
- 2Why are my front brake pads wearing unevenly?