Brake pedal goes to the floor when pressed

BIG4

MEMBER
2003 CADILLAC DEVILLE
V8
2WD
AUTOMATIC
150,000 MILES

I hit a speed bump unexpectedly going approximately 8mph. Applied the brakes and they went to the floor. Pumped them and then got some pressure. I used the emergency brake in conjunction with brake pedal to stop the car for the ride home. Previous to this, my traction control light had come on and was present for 2 days. Within those 2 days I just had a radio/amp installed witch required my battery to be disconnected.
Don't know if they touched any fuses in the process.

Thank you in advance for any advice.

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good afternoon,

I would check under the car and look for a leak when you press the pedal. You may have damaged a line going over that bump if it bottomed out.

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

You may have a bad master cylinder and it is rare from just running over a speed bump but needs to be checked.

I would also try bleeding the system if no leaks are found.

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

Roy

ABS Automated Bleed Procedure

Bleeding the ABS System

Important: With 69Q or V4U, perform the Automated Bleed Procedure 2 times.

Perform a manual bleeding procedure. If the desired brake pedal height results are not achieved, perform the automated bleed procedure below.
The procedure cycles the system valves and runs the pump in order to purge the air from the secondary circuits normally closed off during normal base brake operation and bleeding. The automated bleed procedure is recommended when air ingestion is suspected in the secondary circuits, or when the BPMV has been replaced.

Automated Bleed Procedure

Notice: The Auto Bleed Procedure may be terminated at any time during the process by pressing the EXIT button. No further Scan Tool prompts pertaining to the Auto Bleed procedure will be given. After exiting the bleed procedure, relieve bleed pressure and disconnect bleed equipment per manufacturers instructions. Failure to properly relieve pressure may result in spilled brake fluid causing damage to components and painted surfaces.

1. Raise the vehicle on a suitable support. Refer to Vehicle Lifting.
2. Remove all four tire and wheel assemblies.
3. Inspect the brake system for leaks and visual damage. Repair or replace as needed.
4. Inspect the battery state of charge.
5. Install a scan tool.
6. Turn ON the ignition, with the engine OFF.
7. With the scan tool, establish communications with the EBCM. Select Special Functions. Select Automated Bleed from the Special Functions menu.
8. Bleed the base brake system.
9. Follow the scan tool directions until the desired brake pedal height is achieved.
10. If the bleed procedure is aborted, a malfunction exists. Perform the following steps before resuming the bleed procedure:
If a DTC is detected, refer to Diagnostic Trouble Code (DTC) List and diagnose the appropriate DTC.
If the brake pedal feels spongy, perform the conventional brake bleed procedure again.
11. When the desired pedal height is achieved, press the brake pedal in order to inspect for firmness.
12. Remove the scan tool.
13. Install the tire and wheel assemblies.
14. Inspect the brake fluid level.
15. Road test the vehicle while inspecting that the pedal remains high and firm.