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Discussion Starter · #1 ·
The boosters of my street Duetto ('69) are accumulating brake fluid. I still have a soft brake pedal and functional brakes, though it feels too soft, like it needs to be bled. So is the problem likely to be in the boosters, the master cylinder, or both? Thanks.
 

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If the master cylinder is losing fluid into the booster the master cylinder is defective. And, most boosters will be damaged if brake fluid remains in them for long. Wipe the booster out with a damp rag/paper towel to remove as much brake fluid as possible.
 

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If the master cylinder is losing fluid into the booster the master cylinder is defective. And, most boosters will be damaged if brake fluid remains in them for long. Wipe the booster out with a damp rag/paper towel to remove as much brake fluid as possible.
I think Eric is thinking about the hanging pedal boosters here. As your '69 just has a hard line coming from the MC, I don't see how a MC fault can cause fluid to accumulate in the booster. I would guess that the booster itself is defective although I don't have much experience with this part of the brake system. (Been avoiding it :eek:)
 

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In a 69, boosters are totally separate from the MC, so if they've got fluid in the vacuum chamber, the hydraulic seals are unquestionably leaking. Third vote with Bill and Roger.
It's only in hanging pedals that a bad MC can allow fluid leaks into the booster chambers (since they're bolted together and fluid can get sucked from the MC straight into the booster).
Andrew
 

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If you are lucky only the leaky boosters need rebuilding. However, if one or both boosters are leaking fluid I don't think you'll be able to tell for sure if your master cylinder is okay untill you fix (or bypass) the boosters.
 

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I had same problem its costly. I had 3 times rebuild mc by white plains .On 3 time they remanufactured for me new piston for mc (almost died when lost brakes taking a corner at 50 mph).Each time it leaked I lost booster as well. Fluid gets there and eats rubber. Its need to be cleaned right away or you will end rebuilding boosters or buying new ones.
 

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Discussion Starter · #8 ·
Thanks for the advice. Yes, I remain suspicious of the master cylinder based on the soft pedal. Though I don't doubt for a minute that the boosters are faulty as well. I deleted them from the race car, and while disassembling them, noted that the chromed plunger was pitted with rust.
 
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