Master vs Slave Cylinder Failure?

[flipstah]

I lost braking on the Mini this morning and had to smoke a gate. The Mini came out unscathed (thanks, chrome bumper!)

There's no leak of fluid, so it's not the lines. What are the symptoms of master vs. slave cylinder failure? Or should I just replace both?

It went from bite to no bite instantly.

[JustinL]

Is there a slave cylinder in Mini brakes? I can't picture how that system would work.

Also, can you describe the symptoms more specifically? Did the pedal go to the floor and stay down, or come back up? Did you still have the pedal, but no stopping force?

[flipstah]

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Is there a slave cylinder in Mini brakes? I can't picture how that system would work.

Also, can you describe the symptoms more specifically? Did the pedal go to the floor and stay down, or come back up? Did you still have the pedal, but no stopping force?

There's a master cylinder, and two wheel cylinders apparently? Front and back.

I won't know for sure until I check underneath.

When I initiated contact, it had bite then it just lost pressure and had no brakes. So my foot went pedal to the metal when I hit the gate.

Aftewards, I can still pump the pedal but no catch.

Pedal travel just went from 'pretty good' to 'I regret nothing in life'

EDIT: Just looked up a wheel cylinder was. It's for drum brakes, which only exist on the rear. My front brakes are disc.

[RickDaTuner]

If its the slaves, there you'll have to remove the wheels and looks for wetness and leaking in the brake drums.
If its the master then there will be wetness around the master cylinder piston, or you can rule out all other leaks, and deduce that the master is the culprit.

[flipstah]

Just looked up more possibilities: could be the servo...

This is going to be a fun Canada Day.

[flipstah]

All my brake fluid is gone from the reservoir but no leak, so the theory is that the master cylinder seal gave way and the fluids are in the servo.

[ercchry]

i'd fill and bleed, with all the wheels off you can investigate all corners and see if it even holds pressure and go from there

[SkiBum5.0]

Get in the car, start the car with your foot on the brake. If you feel the brake pedal depress an inch or so, the servo is functioning. You can only do this once you have the system full and bled as per above post from ercchry