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Discussion Starter · #1 ·
Let me start this off by saying I feel like a complete idiot, I have no idea how this happened from a simple brake pad/rotor replacement

A couple of weeks ago I replaced my front pads and rotors. After re-installation the brake pedal would go straight to the floor when pressed. When compressing the caliper piston, I cracked open the bleeders screw and bleed the brakes with a pneumatic bleeder afterwards. I’ve done brakes on various cars in the past and always used a large C-clamp to compress the piston, this time I have a large set of channel lock pliers hand so I used them. When I realized I had no brake pressure, I figured I compressed the piston too fast and blew a seal in the master.

Last week I bought and replaced the master, hoping it would cure my issue. Bleed the master, and the brake lines again, and still have not brake pressure. My next step was to pull engine codes, I am getting a 17887, with no CEL. I check on Ross-Tech, and it references the brack vacuum pump. I’m not sure if the two are related, everything I’ve been reading about the vacuum pump seems to cause hard brakes.

As of right now, initial pressing of the brakes drops the pedal to the floor. Pressure will build by pumping the brakes. The rotor in the pump spins freely.

I’m planning on pulling the brake lines from the master tomorrow and rebleeding the master and the lines again, unless someone has another suggesion to try first.
 

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You have likely dislodged an electrical connector or vac line to cause the 17887 code.
http://wiki.ross-tech.com/wiki/index.php/17887/P1479/005241

You have not bled them correctly, there is air in the system.
Is this "a pneumatic bleeder" a vacuum bleeder or a pressure bleeder ?
If the latter OK, but if the former that would be the problem.

You need to bleed all 4 wheels in the order, RR, RL, FR, FL.
 

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Discussion Starter · #3 ·
It was a vacuum bleeder that I used. I have since re-bled manually, using the brake peddle, still no luck at this point. I agree that it does feel like air in the line, but so far I've run just under 3 quarts. I did order a motive pressure bleeder yesterday and picked up two more quarts of fluid. The pressure bleeder should be here tomorrow, I'll give that a try after work tomorrow.

Thanks for your input.
 

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You don't need a fancy pressure bleeder to bleed brakes, just have a friend over for a few minutes and do the old-fashioned two-man bleed. It works quite well, and has a better "flushing" effect through the brake lines, as the fluid is pushed faster.
 

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ddrink, you are doing something wrong. It doesn't take 3 quarts to begin with, plus you still have the same problem. Take a brake (ha) and try to think what is wrong...

If you pump the brake pedal a few times, can you build pressure? Do you get any air when you bleed the calipers?
 

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Discussion Starter · #7 ·
Gigi, yes pressure will build if the pedal is pumped, but it won't hold, pedal sinks.

After replacing the master, yes I was getting air from the calipers while bleeding. At this point I'm not getting air, just fluid.
 

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Out of curiosity why'd you crack open the bleeders in the first place if you were just doing front brakes? I usually just open up the cap on the master cylinder and just stuff a bunch of rags around it to catch spillage/overflow then replace any lost fluid. Unless you were planning on doing the fluid anyway.
 

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Discussion Starter · #9 ·
Just the way I've always done it. Since I'm at the caliper compressing the piston, by letting the extra fluid come out the bleeder rather then the master, I can see what is coming out while it's coming out.
 

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Oh okay, that makes sense. A few years ago we did the brakes on my friends jeep wrangler and we accidentally damaged the caliper (the damage wasn't visible, I guess it was something internal). The caliper piston would no longer retract. My hunch is that if the master is okay, you've bled the snot out of the brakes (in the correct sequence) and the vacuum pump seems to be functional, the calipers is definitely what I would take a look at next.
 

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Post #7: Gigi, yes pressure will build if the pedal is pumped, but it won't hold, pedal sinks.

After replacing the master, yes I was getting air from the calipers while bleeding. At this point I'm not getting air, just fluid.
This info would have helped earlier, can you provide any other info such as a pool of fluid on the floor.
If the pedal is not spongy, but slowly sinks to the floor the system is leaking.
Check all parts of the system for a leak, if there is no external leak, it must be the MC either leaking back into the reservoir or into the booster.
 

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There is a possibility you have now air in the ABS pump, and for some reason I have learned that the pedal goes slowly to the floor when ABS pump is not air free. Or fluid is leaking somewhere. If it's not leaking outside (you don't see it on the floor) then it's leaking internally in the MC.
It's kind of hard to estimate what is going on, you seem to have followed the correct steps and actions, but still something is missing...
Is the MC new? Not cheap asian imitation?
 

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Discussion Starter · #13 ·
Tom-

No puddles on the floor, or under the rain tray. The pedal does not feel spongy. With the engine off, I can build pressure and hold it, with the engine running it will build pressure, but then sink. If it is indeed the master, I would assume that it is leaking back into the res, as the fluid level does not change.

Gigi-

Yes, the master I put in is a new TRW. After bleeding again last night with the pressure bleeder and not getting anymore air out of the system I ordered another new master this morning. I was wondering about the ABS module, but I've never messed with one before.
 

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You now seem to be describing a situation where there is air in the system, but if there is the pedal would feel spongy.
If there is air in the ABS you need to run the pump, this can be done with VCDS or by activating the ABS on a loose or slippery surface.
Then bleed the brakes again.
 

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I had a similar situation on the wife's Audi A6. I noticed that the brake pedal would go to the floor if I maintained pressure on it so I ordered a replacement master cylinder. After replacing the cylinder and bleeding the brakes the pedal would go right to the floor. I don't recall if it would build pressure from pumping, but I wouldn't let the wife drive it until I got it sorted out. After pulling the master cylinder and reinstalling it multiple times as well as going through at least 3 quarts of brake fluid from multiple bleeds it never improved. I relented and had the car towed to the nearest dealer. They diagnosed it as a leaking caliper and replaced it. Since I never saw any fluid leaking from the caliper I assume that it was a bad seal that manifested itself during the bleeding process, although I'm not exactly sure how that happened.

If there's a way to pull the brake lines one at a time and plug it you should be able to isolate a bad caliper. When the pedal no longer goes to the floor with the line pulled and plugged from the bad caliper you've isolated the problem.
 

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Discussion Starter · #19 ·
Tonight I tired Captian_Video's suggestion of isolating the calipers. I put a clamp on the front left soft line and the brakes felt amazing, I drove it around the lot a little and was very happy. I ran out and bought a new caliper, installed it and took it for a test drive, again, no brakes. Back on the lift, and clamp off the line, brakes feel great again, so I decided to replace the soft line after it had been clamped the second time, and again, no brakes.
 

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Captain_video, the dealer embellished the repair a little. They probably replaced the caliper that was running fine, but IMO they just bled the brakes and ABS pump. Now, this is a dead subject for you but just for future DYIers :) Like TOm said, if caliper leaks, it leaks outside and you will see fluid on the ground, there is not place for the fluid to go.
Ddrink, at least you isolated the problem to one corner. Maybe you have a big pocket of air that you can't get out? I am not sure... If it would be the ABS pump then the clamp at the wheel won't make a difference.
 
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