ABS Bleed

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Devin Foxwell

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So, my master died in my driveway. Went to put it in drive to leave for work, and my foot went to the floor. It appears to have leaked into the booster. So after I make my warranty claim for these two components that are only a year old, i will be replacing my wheel hubs along with master and booster. My abs is disconnected at the module under the hood due to faulty sensors in the hubs. Last year at this time my master and booster died. After replacing, I had a hard time getting a nice firm pedal despite bleeding the s*** out of my brakes. My question is, is the abs module trapping air and causing issues with bleeding? If so, would reconnecting it with the new hubs installed and then triggering the abs free trapped air?
 

east302

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It wouldn’t hurt to have it bled. Though some have been able to burp it by slamming on the brakes in gravel and activating the ABS, a scan tool is required to activate the bleed sequence.

During the sequence, air is purged from the unit (brake pressure modulating valve or something like that) into the brake lines. So, it must be followed with a regular bleed at all four corners.

I’d have a shop do the bleed.
 

Devin Foxwell

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It wouldn’t hurt to have it bled. Though some have been able to burp it by slamming on the brakes in gravel and activating the ABS, a scan tool is required to activate the bleed sequence.

During the sequence, air is purged from the unit (brake pressure modulating valve or something like that) into the brake lines. So, it must be followed with a regular bleed at all four corners.

I’d have a shop do the bleed.

Alright, its gotta go in for an alignment soon. Ill just have them do it then.
 

df2x4

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Make sure the shop you go to has a GM Tech 2 or comparable bi-directional scan tool that can command the ABS module to stay open. Otherwise the shop won't do any better of a job than you can bleeding them.
 

east302

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Good point. I had to tell the tech what I wanted done, he didn’t know that the scanner could do it and thought I wanted just a regular bleed.
 

NightRunner

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If you can't find someone to bleed them, you can take the RWAL ABS out of the equation entirely. I had a really squishy brake feel after one of my wheel cylinders failed. Ended up taking the ABS out and replacing it with one from an S10 turned backwards (but your stock one can do it just fine, I was a dumbass and stripped one of my threads out).
 
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