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Discussion Starter #1
Got in the car today and the brake pedal felt weird-- super easy at first, then super stiff. Clearly something was up.

Popped the hood and there is a puddle under the DSC hydro unit. All of the lines going into it appear to be dry.

Suggestions as to what could be the cause? I'm really hoping "replace hydro unit" isn't the solution, as that's a $2500 (new) part. ouich

Not afraid to get my hands dirty if it can be repaired!



Puddle of brake fluid:



Dry lines:



Not so dry below:

 

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Are you sure that's brake fluid? It appears the AC line is leaking.
 

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Discussion Starter #6
Find a nice used hydro unit with a warranty. Otherwise, new hydro unit.
In talks with clemster for one right now.

Is this a normal failure item? Never heard of it going before.
 

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Take the cover off bet it will be wet inside. Solenoid failure or a short on the board closing a solenoid. If you can do vanos repair then open it up. Not the same but sort of the same.

Bimmer forums ABS module do a search. You can even search here I have posted it twice in the past couple months, and likely 30 times over my past years.
 

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Likely something is stuck open, not opening sort of the same as with the Vanos board. But maybe the seal just failed that looks like an oring. You can test the noids the same as for the boards if they all work replace that O-ring and see how it goes.
 

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Check the two flexible lines leading the DSC unit that run up from below. They run right past the exhaust and I had one of mine blow wide open (thank goodness for dual brake systems). If you're lucky, maybe it's just the hose(s) and not the whole DSC unit.
 

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Discussion Starter #12
Check the two flexible lines leading the DSC unit that run up from below. They run right past the exhaust and I had one of mine blow wide open (thank goodness for dual brake systems). If you're lucky, maybe it's just the hose(s) and not the whole DSC unit.
I replaced them preventively 10,000 miles ago. It's the hydro unit for sure. I have a new one coming Wednesday.
 
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