Brake master leaking

[Brians540ia]

Hi gang,

Has anyone had problems with the booster mounted brake master cylinder leaking on a 540i? There are two lines going into the top of the cylinder and they leak when I'm parked at a slight nose-down attitude in my driveway, but not on a level street. Is there an O-ring that goes bad on these things? I couldn't find anything in my book on the subject.

Thanks

Brian

[Bill R.]

easy to replace.

Hi gang,

Has anyone had problems with the booster mounted brake master cylinder leaking on a 540i? There are two lines going into the top of the cylinder and they leak when I'm parked at a slight nose-down attitude in my driveway, but not on a level street. Is there an O-ring that goes bad on these things? I couldn't find anything in my book on the subject.

Thanks

Brian

[Brians540ia]

easy to replace.

[new540iowner]

RTV Silicone on top of the two black lines to partially seal the leak. If you end up replacing the top two lines, don't you have to bleed the system of air bubbles?

[tim s]

i got new ones from the dealer. no more leak.
tim s.

[Brians540ia]

Hi gang,

Has anyone had problems with the booster mounted brake master cylinder leaking on a 540i? There are two lines going into the top of the cylinder and they leak when I'm parked at a slight nose-down attitude in my driveway, but not on a level street. Is there an O-ring that goes bad on these things? I couldn't find anything in my book on the subject.

Thanks

Brian

[Tiger]

Don't do that... get the seal from dealer... Bleeding is easy... just hook everything back up... leave the cap off... depress the pedal a few times... like 5... but very slowly or otherwise brake fluid shoot out everywhere... and then put the cap on and you are done.