I am unaware of any ABS line bleeding with a TechII. And this car does not require a TechII to bleed the lines (I've bled all the lines on my Monte as they should be done, no issues).

Lines seem fine? Have you disconnected the metal line from the flex line to see if fluid streams out from the metal line when the ? If the flex line is damaged (like I recently dealt with on an F150), you will not see the damage, there is nothing visible as it's internal on the line. And the spongy feel is probably air stuck in the line (hence why you are bleeding it).

If that is not the issue, then the next thought I have is a pinch somewhere in a metal line.

I admit, I have yet to hear of an ABS module fail, so I don't know what symptoms that has. But I'm giving you everything I would look at before the ABS module.

 

You could also have a bad Proportioning Valve. That sits on the master cylinder and has the 4 metal brake lines coming out of it. It could be bad for any combination of your brakes. Also, if your rubber hoses are actually a hose in a hose in a hose. They could be damaged on the inside and you can not tell either from looking or from running fluid thru it. You would have to do a presure test.

 

This is straight from the GM website for your car. The ABS module has 4 individual lines and valves for each wheel and they can get air in individual lines. the tech 2 can scan the abs module and hold pressure on each line to detect an issue. Maniac is right that they don't go bad, in 20 years I've never seen one go bad and there are easier more likely possibilities like a pinched or dirty line. I would guess against the proportioning valve on that since it only breaks it front and rear.




ABS Automated Bleed Procedure
Bleeding the ABS System
Perform a manual or pressure 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. Refer to Brake Fluid Loss or Symptoms - Hydraulic Brakes. 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:

1. When the desired pedal height is achieved, press the brake pedal in order to inspect for firmness.
2. Remove the scan tool.
3. Install the tire and wheel assemblies.
4. Inspect the brake fluid level.
5. Road test the vehicle while inspecting that the pedal remains high and firm.

 

Ok so I will just buy a tech2 probably. Yesterday I actually took the car out on a dirt road to activate the ABS. Will work on it today. Will switch out the master cylinder probably as well.

 

I got it finally. So it was the master cylinder. Took it off my parts Monte Carlo and brakes work great now.

 

Interesting. Well, goes to prove, sometimes there are things just against the odds lol!

 

It actually ruined the 3 days I spent working on it. First I thought it was just the calipers, so I switched them out. Didnt work.... Then I thought it needed to pressure bled which didn't work. Took off the master cylinder, did a bench bleed and put it back on. Didnt work. Was about to buy the tech2 since I thought it was the abs. Glad I decided to switch out the brake cylinder.

 

So the master cylinder was faulty in that it would only deliver partial pressure to 2 lines. Weird, I don't know that I understand that. So you bench bled it, installed it, found low pressure, bench tested it (passed) same problem and it ended up being a bad master still? Was the piston (plunger) not fully operational, hanging up?

 

Thats the question I have been asking myself as well. There is only two lines, an inlet and outlet. Meaning how can only 2/4 lines work? You would think either all work or none of them work. And yes, the way your described is how it went. From what I saw the master cylinder looked fine. The piston seemed to be working as it would suck in brake fluid and pump it out.

 

you may have just dislodged what ever was plugging it up or just all the bleeding finally got the air out. Just be glad its fixed and chalk it up to "I don't know" fixed it.