Soft Brakes?

Suddenly my brake pedal is very soft - goes almost to floor before the brakes engage.

Now if I have the engine off, pump the brakes once, then the pedal is normal.

So its only soft when engine is running.

Is this the master cylinder problem I've read about on the forums?

Fluid level is fine.

Thanks,
2000 Silhouette Owner

Give your brakes a good inspection especially the rears. If there out of adjustment the pedal will be low.

If everything looks normal, no leaks, and properly adjusted the master might be your problem.

Airjer is spot on I think...Just got this 99 silhouette with very weak brakes. Replaced front pads even though they didn't look much thinner than new pads...Helped alittle..So I pulled back drums off and found the rear shoes to be in pretty good shape too...Only thing , they needed adjusting out some more... Did that on both sides and brakes feel 99% better..