encoder

Hey guys,

I was drying off my engine compartment after a wash yesterday and I noticed that the brake fluid reservoir was completely empty.. well below the min line.

I CAN see a small amount of fluid at the very bottom of the reservoir where it's connected to the brake line.

I don't see any signs of leakage. However, all my pads still have a very good amount of life left so it's not as if the pistons are all just fully extended I wouldn't think.

The car has 23.7k. I bought it CPO at 17k and it had a brake fluid change at that time. That was in August.


Before I call my SA i wanted to see if anybody has any experience with this?

jctevere

That's odd. Perhaps you have a leak somewhere? Also, I thought I heard someone say that our cars have a brake fluid level warning if it gets too low. If I'm not mistaken they said the warning would show up when they were going around turns (and it turns out their level was fine). Faulty sensor. But I might not be remembering a w204, it could be a different model.

Anyway, none of us will really know for sure. Only the dealer will know, so bring it in. If its still under warranty it should be covered. (At least IMO).

noka

The 2009 C-Class Operator's Manual says: "Vehicle status messages in the multifunction display" -> "Check Brake Fluid Level" is a possible message. So there must be a low level sensor.

RLE

The brake fluid reservoir sits on top of the master cylinder and is divided into two chambers, one for the front brakes and one for the rear. The front chamber is much larger than the rear one. I just looked at mine with a strong light behind it and I can just barely make out the vertical divider. The level sensor is right on top with an electrical plug on it and I don't see how you can miss it. It looks like it monitors the front chamber only. When filling an empty reservoir it sometimes takes a little while for the fluid to pass from the rear to the front and it might be that it was never full although that doesn't explain why the warning light isn't on.

MB brake fluid reservoirs (and everybody else's) have been built this way since the introduction of split master cylinders.

encoder

thanks for your reply.

Funny, there's this dried (has a texture of dried paint) orange spots on the top near the sensor... Stands out in an otherwise clean engine compartment that was detailed just 6k miles ago.

The second picture is a side profile shot.

I know they're crappy phone pics

Carsy

Top it up a little before using. Check for brake fluid dampness around calipers.

encoder

It's under warranty still (obv), I have an appt w/ my SA tomorrow morning. I'll update when I'm done there. Thanks for your help guys.