Bleeding brakes with ABS?

SIXFAIRVIEW

MEMBER
2004 CHEVROLET SUBURBAN
V8
4WD
AUTOMATIC
40,000 MILES

I replaced all 4 calipers and the master cylinder on my 2004 Suburban. I performed the manual brake bleed as the service manual says. I did this multiple times and get no air bubbles at the calipers. When the engine is off I can pump the brake pedal a few times and it builds up pressure nicely. When I start the engine and try to pump the brakes the pedal goes to the floor. My feeling is that the ABS system is at fault here. I am not getting an ABS light on the dashboard. In the service manual under ABS it states that there is an automated bleed procedure that can be started with a scan tool. My question is, is there a way to initiate this automated bleed procedure without a scan tool? If not is this scan tool a special dealer only scan tool or can I use one of the many aftermarket scan tools?

Wednesday, October 7th, 2009 AT 6:50 AM

3 Replies

SERVICE WRITER

MECHANIC
9,123 POSTS

Couple thoughts on this one.

Why did you did all of this work? Initial problem?

I have had some success with taking a vehicle like this up to 30 mph and then jamming on the brakes to cause the abs pump to cycle and in essence removing air out of it. The scan tool automated procedure may be needed, and is not able to be intiated optherwise as far as I know.
Obviously do this with care.

Did you replace the pads, and rotors?

These brake pads need to be grooved out so they can move back and forth and lubricated as well. Were the pads freely able to move?

Plug of the lines going into the master cylinder and press on the brake, it should be rock hard. Maybe bad master? Hoipefully this was a new one and not a reman.

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Wednesday, October 7th, 2009 AT 7:56 AM

101GMBLR

MEMBER
3 POSTS

2005 silverado 4wd auto rear drum had same problem replaced everything but lines and abs. Replaced new master with another new master same problem, original one leaked out back. Turns out the new booster was bad replaced with another new booster, great peddle even while running old booster full of fluid from a bad master. So I was gonna test drive never made it out of the driveway almost ran over my trailer had to put in neutral to stop. Everything has been bled numerous times even with my autel scan tool brake bleed. So now I am leaning towards a bad abs pump. Hope your having better day!Getting frustrated!

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Monday, December 30th, 2019 AT 1:02 PM

TOUGHDIVER

MECHANIC
224 POSTS

Hi;
I really think you are not getting all the air out of the brake system, Don't read to much into the ABS brake system for this can be done without a scan tool, and you need to bench bleed the master before installation. This video will help

https://youtu.be/WDxvEQrMkBg

You need to bleed from the source in this case will be the Master Cylinder, you can bleed the calipers until you wear out the bleeders and you still will not have a good brake pedal. Have a helper and start at the rear line on the master cylinder one pump hold the pedal down than crack the line open let all the air out tighten the nut and let pedal up, Waiting 10 to 15 seconds between pedal pumps, (Do not rush this you will end up with bad results), Bleed the rear line of the master cylinder until you do not see any air bubbles coming from the line nut fitting, Do the same process to the front line of the Master cylinder, ( Keep checking the reservoir fluid level do not run the reservoir dry or you will need to start all over again). This video can help

https://youtu.be/nQRnKyVyMuQ

Starting at the right rear wheel it is farthest away from the master cylinder, Do the same process pump the pedal one time hold down and open the bleeder let the air out and tighten the bleeder and let the pedal up, Wait 10 to 15 seconds between pedal and bleed until all the air is gone at the bleeder, (Take your time wait for the fluid to fill all the reservoirs in the braking system before each pump), Next do the left rear, right front and the left front, Check the braking on the road test for braking power.
(Make sure all brakes are adjusted to specs). Please let us know if this bleeding procedure was helpful and if you need any more information.

Thank you
Joe Terwilliger

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Monday, December 30th, 2019 AT 3:41 PM