Soft brakes, air leak?

[MR.LUGO]

Hey guys, bled my brakes yesterday due to the pedal being very soft and spongy and pretty much hitting the floor, now after the pedal is stiff at first and then softens up and is hard at the bottom again which is even sketchier than before because it brakes unevenly. What are some signs that it might be the master cylinder or brake booster? Thanks!

[Earendil]

Subed.

[kickinindian]

in for more info!

[FLG]

Losing any fluid? If you pump the brakes do they return?

Looks like a master cylinder issue.

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[Andy.B]

Bad booster would cause a vacuum leak and constantly stuff pedal.

Sounds exactly like a bad matter. Push rod seal is holding, but the internal seals are leaking past each other.

Sounds exactly like mine before I replaced it.

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[MR.LUGO]

Losing any fluid? If you pump the brakes do they return?

Looks like a master cylinder issue.

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I don't think so, i was thinking it could be the lines. Yea the pedal does return.

Bad booster would cause a vacuum leak and constantly stuff pedal.

Sounds exactly like a bad matter. Push rod seal is holding, but the internal seals are leaking past each other.

Sounds exactly like mine before I replaced it.

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Sooo what exactly did you replace? Haha

[DEW]

I think he meant bad master. As in bad master cylinder.

[MR.LUGO]

I think he meant bad master. As in bad master cylinder.

Ah, i see. Makes sense. Well i guess it wouldn't hurt to replace it. Hopefully that'll do it. Thanks!

[Earendil]

Ah, i see. Makes sense. Well i guess it wouldn't hurt to replace it. Hopefully that'll do it. Thanks!

Couldn't hurt?
I suppose I don't know what people's budgets are for these things, but the two places I found online that would sell a brake master cylinder were pushing $200+

If I can rebuild calipers, differentials, and heads, I should be able to buy a $20 gasket set to rebuild a Brake MC instead of dropping a track days worth of money on a new one. Or am I missing something? I hope I'm missing something.

[FLG]

Just replaced mine with a 740il Mc (25mm) and love it. Brakes are super firm.

Paid 135ish for a new ate Mc

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[MR.LUGO]

Couldn't hurt?
I suppose I don't know what people's budgets are for these things, but the two places I found online that would sell a brake master cylinder were pushing $200+

If I can rebuild calipers, differentials, and heads, I should be able to buy a $20 gasket set to rebuild a Brake MC instead of dropping a track days worth of money on a new one. Or am I missing something? I hope I'm missing something.

Ha i kinda take back my "couldn't hurt" comment, i actually hadn't looked them up, i thought they were closer to 50-80 bucks :/ lol.

[MR.LUGO]

Just replaced mine with a 740il Mc (25mm) and love it. Brakes are super firm.

Paid 135ish for a new ate Mc

Sent from my Galaxy Nexus using Tapatalk 2

Nice i was reading up on that as an upgrade, i thought it was just the 750iL, or is it either as long as it's 25mm?

[FLG]

Nope sorry think your correct.

Believe a 5 series one works too.


I'll get you a pn tonight I have the box at home

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[Northern]

Running into what seems to be the same issue on my ix, planning to replace the calipers with some spares that actually bleed before I actually swap out the master.

[kickinindian]

Master did the trick!

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