Originally Posted by island911 (Post 11374344)

pfft... /\ what do you know about leaky seals... oh wait. :cool:

I assume that the ABS system runs independent of the MC, but really don't know.

Does anyone have a hydraulic diagram for that system?

Originally Posted by aigel (Post 11374306)

A round of thorough pedal bleeding of all 4 corners in the right order produced zero air and pedal still does the same.

You guys are right, pedal bleeding does not require big strokes. But my helpers are not experts, so I am just glad they can do the procedure okay with me under the car. 1) put foot on pedal to build pressure 2) open bleeder 3) Pedal sinks towards floor and about half way down helper announces this 4) close bleeder 5) Pedal up - repeat. Key here, the way I learned it, is that the system needs to be under pressure whenever you crack the bleeder.

My money is on the MC, because an air pocket will give a springy pedal feel like an air shock. You compress the pedal but it can come back up. If it sinks, ever so slowly, that tells me the fluid is leaking past the MC piston seal.

Now what Jeff writes about the ABS unit is worrisome. On two fronts. Maybe I got air in it and that's causing my pedal effect but worse, if I replace the MC, I may get air in the ABS unit as well? I'd get a scan tool and do it all right, but very limited on time these days.

At this point it is either spending more time installing a new MC or throwing in the towel and just get some professional help this week.

What would you guys do next!?

G

Originally Posted by aigel (Post 11374306)

A round of thorough pedal bleeding of all 4 corners in the right order produced zero air and pedal still does the same.

You guys are right, pedal bleeding does not require big strokes. But my helpers are not experts, so I am just glad they can do the procedure okay with me under the car. 1) put foot on pedal to build pressure 2) open bleeder 3) Pedal sinks towards floor and about half way down helper announces this 4) close bleeder 5) Pedal up - repeat. Key here, the way I learned it, is that the system needs to be under pressure whenever you crack the bleeder.

G

Originally Posted by Jeff Hail (Post 11373934)

Need to get the bubbles out and past the ABS pump before and after the pump. If any air gets in the servo chamber/ accumulator you are not going to get it out by pumping the pedal.

The ABS section of the brake system cannot be bled without the use of the scan tool; there are no manual procedures for bleeding the HCU. Using the scan tool, select ECU VIEW, then select ABS MISCELLANEOUS FUNCTIONS to access the bleeding procedures. Follow the instructions displayed on the scan tool.

Think of it as two systems:

Bleed the calipers/ cylinders first.
Left rear wheel
Right front wheel
Right rear wheel
Left front wheel

Then bleed the abs system.

With the ABS bleeding completed, bleed the base brake system a second time using the same procedures that were outlined for bleeding the base brake system the first time. Once again, check the fluid level in the master cylinder and be sure that it is at the FULL level.

Originally Posted by rusnak (Post 11374920)

Have the helper pump the pedal several times, then hold it down hard like in a panic stop. Open the bleeder screw with the helper holding the pedal down. If there is air, it'll come shooting out like crazy. Put a block under the pedal to keep it from going to the floor.