Brake fluid LEAK.
 

Good day people,

I just replaced aces all four of my pads and disks on my 2010 MCS, all went fairly smoothly however just as I finished I noticed a big pool of fluid under the master cylinder.

I get the concept of pushing the fluid back causing the resevouir to fill back up and that previous services may have topped up the fluid my my question is:
could I have broken something when compressing the pistons to fit the new pads in?

Please ser tell me that this is normal? I haven't found a similar post...

also so this could be because I'm hyper aware afterwards but pressing the brake whilst stationary I hear a click-clack from the center console area but nothing when outside?!

Thanks in advance.

AusMCS

clean the are and fill it up again. keep and eye on it and see where the leak is coming from.

Very unlikely that you broke something when pushing the pistons back to fit the new pads. Consider the pressures that develop in the braking system when you stomp on the brake pedal, you can easily put 100lbs of force on the brake pedal which gets amplified through the master cylinder to the individual pistons. Most likely the master cylinder overflowed and you are seeing the result. I hope you cleaned it off quickly as brake fluid will eat the paint.

The noise you are hearing is probably the brake light switch and/or the pedal mechanism. In my go-pro videos from my track days I can hear a particular "clunk" noise very clearly when I take my foot off the brake. This comes through even with the noise from the wind and engine.

The click heard in the center console while pressing the brake pedal is most likely the shift interlock solenoid if you have an auto trans. And all you did was push extra fluid out of the top of the brake master while compressing the brake pistons back in. Not really an ideal situation with ABS and all, as you could push debris from the brake pistons back into the system, possibly contaminating the ABS pump. The recommended method is to open the bleeder on each caliper before compressing the pistons. That way all the dirty stuff in the calipers doesn't get into the ABS motor and control valves. And, YES, be sure to wash that brake fluid off of any painted surfaces. Brake Cleaner is preferred, but water should flush it away as well.