Breathers on single-line brake master cyl?s?
Turbo Mini Forums

I?ve always had a problem with brake fluid vapours making a mess of my engine bay around my master cylinders (both brake and clutch are single-line bean-can style). After a few miles of general driving, I?ve got brake fluid sat in the recess on top of the reservoir, and a film / spots of fluid on my bulkhead.
It?s ALWAYS done this, but I?m not really sure why ? or if it?s just the brake master that is doing it (it is worse on the brake than clutch master).

I?m sure I saw a race mini once that ran breather pipes from the tops of his master cylinder lids, but not seen it (or any others) since.

Oh ? I?ve tried putting O-rings at the bottom of the threads, but the actual caps seem to be a two-piece vented design, so it still happens. Also tried the extensions, but the same thing happened, and i could never get them to seal at the bottom.

Incidentally, Both Master cyls were brand-new Lockhead items 6/7 years ago, but this has always happened. Enough is enough!


So, am I the only person in the world who experiences this? Any suggestions?

Just a thought....how full to you top your master cylinders up to? Maybe running _SLIGHTLY_ less fluid would lead to less likelihood of it blowing out of the top?

after MANY years with wrestling with 1000s of cars dave

i have never heard or come across this one ?????

first attack would be toms approach then

air in the system sounds the likley cause


i would be tempted to look in the direction of the rear shoes and drums not concentric causing peday knock back to the master cylindar??

then i would clock the front discs for the same

having said that the givaway likley cause would be the master cylinders as its happning on both!

could it be slight pedal knock back from the clutch ie the pressure plate may be not rinning true ? causing this ?

i doubt it !

its the fluid not up to the job is my bet

or the cylinders ar shite, duff

hope this has inspired you to think the problem through!

ben

mine always used to do this to (even with the extensions), never did figure it out

hopefully remote resevoirs will stop it!!

only 1 had this do it too, was the seal on the bottom of the extension leaking.

never happened to mine, but then I had fitted a new master cylinder. Do you top it up beyond the mark?

I donated, but somehow didn't get the label! :(