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Brake Fluid Spraying Out The Back Of The Brake Booster


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I have a good-sized a brake fluid leak in a customer's 2002, leaving puddles and visibly draining the reservoir. I crawled beneath it and had someone pump the pedal while the engine was running with me I looking up, trying not to get brake fluid in my face. When the pedal is pumped, I'm seeing a spray of brake fluid out the back of the brake booster, where the linkage goes in. I am I correct that this is probably a bad seal between the master and the booster, and that the master probably needs to be changed but the booster itself is probably okay?

 

--Rob

The new book The Best Of The Hack Mechanic available at https://www.amazon.com/gp/product/0998950742, inscribed copies of all books available at www.robsiegel.com

1972 tii (Louie), 1973 2002 (Hampton), 1975 ti tribute (Bertha), 1972 Bavaria, 1973 3.0CSi, 1979 Euro 635CSi, 1999 Z3, 1999 M Coupe, 2003 530i sport, 1974 Lotus Europa Twin Cam Special (I know, I know...)

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That sounds like a bad Brake Master has been blowing fluid back into the Booster causing the vacuum diaphragm to rupture. In other words the Booster should now be DOA......

I don't take myself or opinions Seriously

My 4th 2002 and the first set of Square Tail-Lights

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+2...rear seal on the M/C has "turned up its toes" and is peeing into the brake booster.  You might be able to salvage the booster by removing it, draining out all the accumulated fluid and then seeing if it'll hold a vacuum.  However, the fact that fluid is coming out the back side of the booster (the firewall side) indicates that the diaphragm has a hole in it.  

 

Somewhere in the archives there's info on one or more places that rebuild boosters...

 

cheers

mike

'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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I've drained out a few boosters, and they've all survived the process.

 

I can't imagine why the car's not puking a ton of white smoke... if the vacuum's hooked up.

 

Maybe the booster's already dead!

 

t

"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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I think a std yearly PM is in order to use a piece of wire and clean out the inter seal bleed hole on the bottom of the MC so the fluid, if the MC begins to leak, squirts out the vent rather than pushing into the booster.  That's what the vent is there for.

A radiator shop is a good place to take a leak.

 

I have no idea what I'm doing but I know I'm really good at it.

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