Brake bleeding procedure

Yes, this is a big problem with bleeding the brake on an ABS system unfortunately a scanner is the most popular way to bleed the system, but I have heard of people triggering the solenoids manually using a wiring diagram. You will need to open the unit up to find the wires to each valve.

Please let us know what happens.

Cheers, Ken

This guide can help us fix it with instructions below.

https://youtu.be/w7gUsj2us0U

and

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

Try a few hard stops on a Gravel road, or grassy area this usually dislodges the traped air in the ABS sytem, and can then be bled out. Only other way is a GM Tech II tool to command the abs mod to bleed.

When you installed the new master cylender, was the pushrod adjustable? Also, does the pedal only go to the floor when the engine is running?

I have one more question. Have you checked the rubber brake hoses? When you hit the brakes with the engine running, check to see if one is expanding. If that isn't it, I am going to say either you got a bad master cylender (that is allowing fluid to bypass the plunger) or it has to be a hose or leak at some point.

Check the hoses and let me know what you find. I have seen them blow up like a baloon when too much pressure is placed on them.

Joe

I look forward to hearing from you.

Joe

Good morning,

It could be air in the ABS unit or it could be the hose in the rear to the bleeders.

I posted the bleeding below for you. There is a process for bleeding the ABS unit and you need a scan tool for this procedure. Then you can do you normal bleeding procedure.

Roy

ANTILOCK BRAKE SYSTEM (ABS) BLEEDING PROCEDURE

NOTE:
The two person bleed procedure is required when installing a new electro-hydraulic control unit, or when air is suspected to be trapped in the valve body.
Do not run the scan tool Function Test after combination valve or tube adapter replacement.
Do not drive the vehicle until brake pedal feel is firm.
Do not reuse brake fluid used during bleeding.
Vacuum, pressure or gravity bleeding may be used for base brake bleeding only.

1. Raise and support the vehicle to gain access to the system bleed screws.
2. Begin by bleeding the system at the right rear wheel.
3. Install clear hose on the bleed screw. Immerse the opposite end of the hose into a container partially filled with clean DOT 3 brake fluid.
4. Open the bleed screw 1/2 to 1 full turn.
5. Slowly depress the brake pedal until it reaches its full travel and hold until the bleed screw has been tightened. Release the brake pedal and wait 10-15 seconds for the master cylinder pistons to turn to the home position. Repeat until clean, air free brake fluid is present at the wheel bleed screw. This procedure may use more than a pint of fluid per wheel. Check the master cylinder fluid level every 4 to 6 strokes of the brake pedal to avoid running the system dry. Repeat steps 3 though 5 on the left rear, then right front, then left front.
6. Use the scan tool to run Function Test four times consecutively while applying the brake pedal firmly. Remove foot from the brake pedal between each test.
7. Rebleed all four wheels using steps 3 through 5 to remove the remaining air from the brake system.
8. Evaluate the brake pedal feel before attempting to drive the vehicle and re-bleed as many times as necessary to obtain appropriate pedal feel.

From what you are describing I would definately be looking for a blockage. When the line blew, contaminents where sent throught the lines. I would disconnect the lines from the rear wheel cylinders (or calipers for rear disc) starting with the RR. Pump the pedal just enough to check for flow. If you have fluid flowing out then your wheel cylinders(or calipers for disk) need to be replaced due to debree restricting your bleeder. Repeat check for LR. If this does not work then you may have a valve stuck in your master cylinder assembly that is not allowing fluid to transfer to the rear.