Pedal on the floor

Tiny
VENOMVETTE
  • MEMBER
  • 2006 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 189,000 MILES
As soon as turning truck on brake pedal sinks. When driving push half ways down and nothing happens. Followed the entire brake lines no leaks.I have done new master cylinder, drum rotors, pads, rear wheel cylinders, brake fluid flush, and bled ABS with a scan. Feels exactly the same.
Tuesday, May 21st, 2019 AT 5:44 PM

5 Replies

Tiny
VENOMVETTE
  • MEMBER
  • 4 POSTS
The vacuum hose is in good condition. And the shoes have been adjusted just before they contact the rotors.
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Monday, February 22nd, 2021 AT 5:20 PM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

This could be a problem with your brake pedal adjustment. You need to have the brake pedal on your vehicle at the right height for it to work properly. Using the guide in the diagrams down below you should be able to adjust your vehicle's brake pedal to the proper height. Please get back to us with what you are able to find out.

Thanks,
Alex
2CarPros
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Monday, February 22nd, 2021 AT 5:20 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 POSTS
Welcome to 2CarPros.

Try rebleeding the ABS. If there is air in there, it will cause this. Also, before you bled the ABS with the scanner, did you manually bleed the system? It has to be done prior to the automated bleed procedure.

Here is what I have for the automated procedure. See if it is the same as you have.

ANTILOCK BRAKE SYSTEM AUTOMATED BLEED PROCEDURE
ABS Automated Bleed Procedure

Notice: When adding fluid to the brake master cylinder reservoir, use only Delco Supreme II, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

Notice: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Service Precautions.

Important: This procedure may be performed on all vehicles EXCEPT those equipped with option code JL4, Vehicle Stability Enhancement System (VSES).

Important: The base hydraulic brake system must be bled before performing this automated bleeding procedure. If you have not yet performed the base hydraulic brake system bleeding procedure, refer to Hydraulic Brake System Bleeding (Manual).

1. Install a scan tool to the vehicle.
2. Start the engine and allow the engine to idle.
3. Depress the brake pedal firmly and maintain steady pressure on the pedal.
4. Using the scan tool, begin the automated bleed procedure.
5. Follow the instructions on the scan tool to complete the automated bleed procedure. Release the brake pedal between each test sequence.
6. Turn the ignition OFF.
7. Remove the scan tool from the vehicle.
8. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme II GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
9. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Manual).
10. With the ignition OFF, apply the brakes 3-5 times, or until the brake pedal becomes firm, in order to deplete the brake booster power reserve.
11. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.
12. If the brake pedal feels spongy, repeat the automated bleeding procedure. If the brake pedal still feels spongy after repeating the automated bleeding procedure inspect the brake system for external leaks. Refer to Brake System External Leak Inspection. See: Hydraulic System, Brakes > Component Tests and General Diagnostics
13. Turn the ignition key ON, with the engine OFF; check to see if the brake system warning lamp remains illuminated.
14. If the brake system warning lamp remains illuminated, DO NOT allow the vehicle to be driven until it is diagnosed and repaired. Refer to Symptoms - Hydraulic Brakes. See: Hydraulic System, Brakes > Symptom Related Diagnostic Procedures
15. Drive the vehicle to exceed 13 kph (8 mph) to allow ABS initialization to occur. Observe brake pedal feel.
16. If the brake pedal feels spongy, repeat the automated bleeding procedure until a firm brake pedal is obtained.

__________________________________

Let me know.

Joe
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Monday, February 22nd, 2021 AT 5:20 PM
Tiny
VENOMVETTE
  • MEMBER
  • 4 POSTS
Thanks for the reply. Alright I followed all the procedures I don’t get step 5 saying release pedal between each test. On my scan tool tells me to press down and never release pedal until tests are complete. Then says complete no faults found. I have never had the ABS lights on pulled fuse just to make sure they light up. Which they do. Bled all the brakes RR, Rl, RF and left front. Push pedal and it’s stiff as soon as the truck is on and I push in the pedal sinking right to the bottom and stays soft.
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Monday, February 22nd, 2021 AT 5:20 PM
Tiny
VENOMVETTE
  • MEMBER
  • 4 POSTS
As far for pedal height it’s two feet normal rest no pressure. Two feet four inches engine off all the way can push down. And two feet six inches truck on all the way pushed down. Don’t even see anywhere you would adjust height on the brackets.
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Monday, February 22nd, 2021 AT 5:20 PM

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