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Brake Light Is ON

Posted: Mon Dec 05, 2011 9:44 pm
by StreetLegacy93
My Brake light is on constantly and i checked the fluid and its right near max.

the brakes stop really well but start to engage at about 60% down. not sure if that is normal on older cars?

I'm thinking its the e brake indicator wire or sensor that is stuck.

If anyone know what it could be or what i should check that would be great, Thank you!!

Re: Brake Light Is ON

Posted: Mon Dec 05, 2011 10:03 pm
by vrg3
The floating part of the sensor sometimes gets stuck. It's a little magnet floating in the master cylinder reservoir; there's a reed switch mounted underneath it that gets tripped if the magnet gets close enough. Try giving the floating part a little jiggle.

Re: Brake Light Is ON

Posted: Mon Dec 05, 2011 11:20 pm
by StreetLegacy93
hmmm im not seeing it, do u have any pics I can refrence?

thank you

Re: Brake Light Is ON

Posted: Tue Dec 06, 2011 7:00 am
by vrg3
This is a from-above view of a brake master cylinder reservoir (courtesy of Legacy777): http://www.main.experiencetherave.com/s ... P_4150.JPG

The float is that little vaguely H-shaped plastic thing right in the middle of the reservoir.

If yours is missing, that'd definitely be your problem.

Try unplugging the connector for the level sensor. If the light turns off, the level sensor is being tripped one way or another.

Re: Brake Light Is ON

Posted: Tue Dec 06, 2011 8:11 am
by StreetLegacy93
awesome ill give it a try, thnx

Re: Brake Light Is ON

Posted: Wed Dec 07, 2011 11:04 pm
by StreetLegacy93
i just looked at the master and when I took the cover off there was a rubber black thing all messed up so I unfolded it and places it back inside the groves where its from put brake fluid in and light turned off!

maybe that fixed it, if not ill take it to subi it needs an oil change and they said they do a 25pnt inspection free with n oil change.

Re: Brake Light Is ON

Posted: Thu Dec 08, 2011 6:35 am
by vrg3
Ah ha.

That black rubber thing is part of the master cylinder cap. When the cylinder is filled with brake fluid, you fold it into the grooves like you just did. Then, as the level drops due to pads wearing, the vacuum in the cylinder draws that rubber gasket thing down, thereby evening out the pressure in the reservoir. This design allows the vacuum to be relieved without having to expose the brake fluid to air, which causes it to deteriorate.

Whoever last worked on your brakes must have forgotten (or not known) to push it back in after the fluid level was back to the full level, so it was pushing down on the float, tripping the fluid level switch (because the float was sitting low as if the fluid level was low).

Your problem should be fixed, but it might be worth quickly inspecting the whole brake system to make sure it's in good shape, since it looks like it might have been serviced by someone who didn't fully know what he or she was doing.

Re: Brake Light Is ON

Posted: Thu Dec 08, 2011 6:47 am
by StreetLegacy93
Yes i have an appointment at Subaru friday for an oil change i'll just have them look it over and let me know what all wrong! get the most important things fixed fist.

Re: Brake Light Is ON

Posted: Thu Dec 08, 2011 5:54 pm
by subydaddy
There may be a leak in the brake system. How's the level after you pushed that black rubber thingy back in? Have you changed brake lines? Keep on eye on your level and that black thing. If it's blown out the next time you take your master cylinder cap off, you have a leak.

Re: Brake Light Is ON

Posted: Thu Dec 08, 2011 6:20 pm
by StreetLegacy93
Awwww.... i do have a leak that is for sure! just gonna replace the whole lines, unless i can find a shop to do it cheap. 200 or less and i'll have them do it cuz i dont wanna deal with it