taverty

I have an 09 G37S with ~51K miles.

I'm having strange issues with my brakes. Shortly after starting and driving my brake light comes on for a few seconds and goes back off. It may do this 2 or so times, but after 2 miles or so it doesn't do it for the rest of the trip. The brake reservoir has plenty of fluid so it's not because the fluid is shifting.

On closer inspection of the master cylinder it looks like the seal between the master cylinder and brake booster was leaking at one point. The paint is all bubbled on the brake booster right where the master cylinder connects. Feeling there now it's completely dry. I can peel off the paint.

I also always seem to have trouble keeping my front brakes from leaving dark spots on the back of the rotors. I recently indexed my rotors and they is no more than .002 runout. But I can't seem to get rid of the dark spots and the shimmy when braking at highway speeds.

Does anyone happen to have any insight as to what could be causing the random brake light in dash? And dark spots on the rotors?

Thanks in advance!

landslide03

iTrader: (1)

Is it just one dark spot like the impression of the pad or is it like a spot going all around them? From what I have heard usually seals don't go bad on master cylinders usually the mc go bad all together but I have had the paint peel off my other cars when either I over filled it or pushed the pistons back in and it over filled. How dirty is your brake fluid? Maybe some dirt or debris got in the sensor and is giving u false readings. I know on some of my other sensors I had to ohm them with my multimeter to see if they were still good.

landslide03

iTrader: (1)

Any luck figuring what was wrong with you brakes?

taverty

Hey landslide03, sorry for the delay, got side tracked with my other car. I swear they talk to each other and decide to have issues at the exact same time!

I still haven't found out the issue. The dark spots are dark thick lines, about 4 or so of them evenly spaced around the rotors. They're a little sticky, or rough feeling compared to the rest of the rotor. Strange thing is that they're only on the back of both front rotors, no where else. I definitely think these lines are causing the vibration when braking.

The fluid looks like a nice light beer and fairly clean. I agree, I feel like the peeled paint is from someone overfilling the reservoir not from a leak since it's all dry now.

Maybe I'll flush the system to see if that fixes any issues.

Any idea at what level the brake light should come on? The reservoir is half way between min and max so I didn't think that should be low enough for the fluid to slosh around and trigger the light.