# B5 Passat bleeding issue



## vdubcab86 (Apr 8, 2007)

I've got a 11/99 Passat at my shop, and I am running into an issue I haven't seen before. The car came from another shop after having the front pads replaced. Immediately after, the brake pedal goes right to the floor without resistance. The brakes do engage but only at the floor. I have tried to bleed them, but I can only get fluid out of the RF and LR. I only get a trickle out of the LF and RR. I have scanned the car with VAG-Com, but there are no codes present for the ABS. I am wondering if the ABS module is damaged, or if there is a metering valve I am missing, or if the master cylinder is damaged. I have tried to activate the ABS in hopes of getting fluid to equalize in the system, but no such change.
Anyone else run into this? Any help is appreciated. Thanks in advance. http://****************.com/smile/emthup.gif


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## spitpilot (Feb 14, 2000)

*Re: B5 Passat bleeding issue (vdubcab86)*

My understanding is that if air is let into the system above the ABS valve block..say by letting MC run dry or changing MC, lines etc...then you need to use VAG to "cycle the ABS while bleeding" to get air out of the valve block..normal bleeding methods won't do the job. http://****************.com/smile/emthup.gif


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## vdubcab86 (Apr 8, 2007)

*Re: B5 Passat bleeding issue (spitpilot)*

I can understand that, what I don't get is that the system was never "opened". Only pads were put on.


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## vdubcab86 (Apr 8, 2007)

*Re: B5 Passat bleeding issue (vdubcab86)*

I can try to cycle it again, maybe I'm not getting the whole story from the other garage.


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## spitpilot (Feb 14, 2000)

*Re: B5 Passat bleeding issue (vdubcab86)*


_Quote, originally posted by *vdubcab86* »_I can try to cycle it again, maybe I'm not getting the whole story from the other garage.
 Yup..they may have tired to bleed brakes and ran the MC dry!...or if system hadn't been flushed in ages..pump bled it and ruined the MC seals on all the crud build up in the MC bore due to old brake fluid sittin in there for years.


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## vdubcab86 (Apr 8, 2007)

*Re: B5 Passat bleeding issue (spitpilot)*

Probably the worst thing about working on other people's ****e is not knowing what they have done, or more appropriately what they have messed up, because they "didn't know any better".
I appreciate the help spitpilot, if you run into any issues with the older stuff let me know. I'm good with them, new stuff, not so much. Need to buy some bentley's.
Thanks again. I'll let you know what happens.


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## spitpilot (Feb 14, 2000)

*Re: B5 Passat bleeding issue (vdubcab86)*


_Quote, originally posted by *vdubcab86* »_Probably the worst thing about working on other people's ****e is not knowing what they have done, or more appropriately what they have messed up, because they "didn't know any better".
I appreciate the help spitpilot, if you run into any issues with the older stuff let me know. I'm good with them, new stuff, not so much. Need to buy some bentley's.
Thanks again. I'll let you know what happens.

Exactly....everyone knows I like to work on cars..been restoring, maintaining, modding forever...so I get folks sayin.."ZXCZVXC said you were good with cars..can you take a look at my problem?"...Of course they don't tell me what has been done/happening to car recently...much ezier to work on cars "under your care"...like a family doc, you know what's been goin on all along..jumpin in the middle is a PITA..I try to avoid it!


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## vdubcab86 (Apr 8, 2007)

*Re: B5 Passat bleeding issue (spitpilot)*


_Quote, originally posted by *spitpilot* »_
I try to avoid it! 

Yeah, "try" is the key word here...


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## GTijoejoe (Oct 6, 2001)

*Re: B5 Passat bleeding issue (vdubcab86)*

I would get a brake pressure gauge and hook it up at the caliper's pipes that you are not getting to lock.... see where the pressure is hiding. 
NO pressure at this locations, and I would go further up the system until you are directly out of the MC port. This is a handy method to understand if its post modulator or pre. Could very well be the MC, or something as simple as a blocked passage.
It is possible to get air in the modulator when there is an open air passage above it, but normally when the modulator is already filled with fluid (and not cycled with air), air should pass straight through the block no problem. The block is sealed from the pump portion..... When we do not have the means to vacuum fill an entire brake system and we need to change the modulator, we get them 'wet' from the supplier, meaning the pump is cycled with fluid to fill its internals and then plugged.
hope that helps


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## vdubcab86 (Apr 8, 2007)

*FV-QR*

Turns out the M/C was bad. I replace the valve body as well, just in case.
Hey thanks for your help guys, I really appreciate it. I know the older watercooled well but not the newer ones. Time to do some more research so I have these under my belt.
Thanks again.


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