Re 2010 Acura MDX This may be perfectly normal but I never experienced or noticed it before. Replaced brake fluid as usual using my Vacula bleeder. Started car and could not get a firm brake pedal. Just kept going to floor. Turned car off and pedal was firm. Turned car back on and braking was normal. Can anyone explain this? At first I thought I let air get into the MC but that just could not have happened because fluid level was always well above ram. Thanks for your thoughts.