I rebuilt one front caliper on my 300SD because it the piston was stuck in the bore because of rust and since then the master cylinder looses fluid but I don't know where it is going. There are no visable leaks from the caliper I rebuilt. I filled the master cylinder 2 times and it is now empty again and of course the brakes don't work.

Anybody have a clue where the brake fluid is going? Can it be fixed without replacing the master cylinder?

P E H

Is there some way that the fluid can make its way past a bad master cylinder, into the power brake booster and through the vaccum system into the engine?

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

PEH, just ignore what I am about to say... it is directed at everyone EXCEPT you....

For people who are about to do anything to their brakes.... or suspensions in general... Everything I have read in the last 40 years says that repairs are to be done PER AXLE.... in other words....if you repair one caliper you do the one across the car from it.... same for shock absorbers, ball joints, etc..

Now, back to regular programming...

PEH, if you have cleaned those areas and have nothing on the ground.. then there is a good chance Eric is correct...

Another possibility is that the brake fluid is leaking from the master cylinder into the cabin area, and is being absorbed into the soundprofing / carpet.
Is this possible on MB vehicles?

I will bet you its getting sucked into the brake booster. Thats what happened to mine. That cost me a remanufactured master cylinder AND a remanufactured Brake booster. Pull the master cylinder off. if the booster is full of Brake fluid they are both toast.

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Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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