Hi All,

Today I discovered a good sized oil spot in the carpet behind the brake pedal. It was damp and the carpet was soaked through. Since its been about three years since I'd had the mats out and vacuumed, I have no idea how long it's been there. Any ideas of its source? The car doesn't have a history of needing to have any of the fluids topped off.

Thanks for your help!

Rachel

If it is your Master Cylinder, and at least from the description sound like it, brake fluid is very nasty on metal. Try your best to clean it up, even lift the carpet were it puddled on, if a lot leaked, you might want to consider pulling the carpet out and trying to wash, or replace. The brake fluid is hard on metal, and your car floor could start to rust from the inside out.

Is the liquid sweet smelling and greasy? It could be coolant from heater control valve or heater core.
Bill

Two possibilities not yet mentioned:

Could it be grease instead of oil? If so, it could have come from the pivot pin that connects the pedal to the master cylinder pushrod and/or the main top pivot for the pedal. I recently had to adjust my brake light switch, and found an amazing amount of grease (easily 10X what was needed) on these two areas. It doesn't take too much imagination to see how some of this could migrate to the carpet and soak in, especially if you live in a hot climate.

The other is that there was previously a problem with the master cylinder, as others have described below, which was repaired before you ever saw the car, and the spilled brake fluid was not cleaned up. This is less likely, as you mentioned "about three years since I'd had the mats out" and you would probably have noticed it then.

It would be a good idea to remove the two nuts and pull the master cylinder forward a bit to check for fluid leakage, as Jorrell suggested (the brake lines are flexible enough that you shouldn't have to disconnect them to do this, but be gentle and don't kink them) If the M/C seems OK, the grease theory is the only other explanation I can think of.

by chance does your car maybe have an aftermarket mechanical oil pressure gauge with a capillary tube that could be leaking?

Otherwise, it's got to be brake fluid, or water... I know it's not the right thing to do, but.. first thing I'd do is a taste test. Brake fluid is quite bitter...

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-Matt I ♥ my ♂

The first thing is to check the brake fluid level, if it is low, unbolt the master cylinder from the brake booster and pull it forward a bit, if there is fluid on the back side flange of the MC, its time for a new MC... at least a rebuild. Otherwise, I can't think of what else would deposit an oil like substance below the brake pedal.

jorrell
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92 245 250K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

Thanks Jorrell - just checked and the brake fluid level is good.

I'm with Jorrell on this. The raer seal on teh Master can go bad and it will let fluid out the back of the Master and inside the car.

Fluid is OK? Hmm, did someone top it off recently, maybe last time you had general service done?

Is the brake pedal soft for the first pump then get hard? It really does sound like the Master.

Are you sure it's oily and not just water?
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

Not to hijack this thread but, I came across something this weekend. Low brake fluid level and a hissing sound from under the dash when stepping on the pedal. Filled up the reservoir and all is well, for now. Should I be feeling a new MC in my wallet pocket about now?

Thanks,
Bill

Most likely,

Yep

Regards,

Paul