Not an SN - but could really use some other brains on this one.

[gate keeper]

The brakes went out before we replaced the booster and the master - so they are both new since the problem surfaced.
We seriously have been daily driving this thing since November - then BOOM out of nowhere on the way back from lunch - NO BRAKES.
So I agree it SOUNDS like a leak - but that is something that would have affected the brakes from the get go - but it was a sudden loss of brakes.

Since then - we've replaced the booster, master and bled everything along the way - I think next we're going to get it up in the air and follow all of the lines from front to back.

 

[rz5.0]

Good luck

 

[gate keeper]

Lol. that's about where we sit

 

[95opal]

The brakes went out before we replaced the booster and the master - so they are both new since the problem surfaced.
We seriously have been daily driving this thing since November - then BOOM out of nowhere on the way back from lunch - NO BRAKES.
So I agree it SOUNDS like a leak - but that is something that would have affected the brakes from the get go - but it was a sudden loss of brakes.

Since then - we've replaced the booster, master and bled everything along the way - I think next we're going to get it up in the air and follow all of the lines from front to back.

Are you saying you haven't noticed a drop in fluid level in the master? With a leak enough to loose 90% of the brakes it should be quit apparent I would think. Have you looked on the interior down by the pedal for any leaks from the master? Even if there's no leak the master may have failed internally and there would be no way to spot it.

 

[gate keeper]

Are you saying you haven't noticed a drop in fluid level in the master? With a leak enough to loose 90% of the brakes it should be quit apparent I would think. Have you looked on the interior down by the pedal for any leaks from the master? Even if there's no leak the master may have failed internally and there would be no way to spot it.

Pulled over as soon as it happened and fluid level was fine, got it towed home and put up in the air - not a single drop of brake fluid from anywhere - also, no leak inside the firewall.
If the Master did fail - we replaced it - with a brand new one, bench bled it and installed it - issue is still the same....

 

[VooDoo95Cobra]

there could be air trapped in the ABS module that you are not able to bleed. A scan tool with the correct functions needs to be used in order to properly bleed the ABS module. Air could have traveled up the lines while you were changing out the calipers. If this is this case, when you have the correct scan tool it will command the ABS module to purge the valves inside. It might tell you to press the brakes at certain times or whatever. There should be a procedure to follow in the scan tool.

 

[95opal]

there could be air trapped in the ABS module that you are not able to bleed. A scan tool with the correct functions needs to be used in order to properly bleed the ABS module. Air could have traveled up the lines while you were changing out the calipers. If this is this case, when you have the correct scan tool it will command the ABS module to purge the valves inside. It might tell you to press the brakes at certain times or whatever. There should be a procedure to follow in the scan tool.

This is also a possibility... If air indeed got trapped in the ABS module...also don't the 05s and up use one reservoir for brake and clutch? ...is it possible air got trapped in the line to the slave or actually in the slave? Just throwing out random ideas

 

[CC'S95GT]

What would happen if he pulled the fuse for the ABS?
I would hope the brakes would work normally with just a light on the dash and obviously the ABS wouldn't work.

 

[chaos254]

I know you replaced the master but we have had bad masters that leak internally. Does it get any better when you pump the brakes?

Sent from my SCH-I545 using Tapatalk

 

[blackdemon007]

Although I'm not real familiar with brake systems in the newer cars, I'll throw in my two cents.

I agree with VooDooCobra, the ABS unit could be a problem, however if that is not the case then it sounds like some sort of electrical problem to me.
Not sure to what extent the brakes on these cars are controlled by electrical components but if they work fine when the car is off and don't when it is on, then this is my suspicion

 

[Mystic SVT]

It sounds like your ABS unit might be the problem here. Might have air trapped inside and VooDoo95Cobra is correct in saying you need to have the ABS module scanned and purged for air in it. We had this problem with my buddy's Cadillac SRX after we did an engine swap (dropped everything from the bottom, disconnected brake lines), we ended up with air in the ABS module and we only had about 30% stopping power, had to take it to one of our friends shop so he could scan the ABS module and have it purge the valves...good as new after that.